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Double Past Sentences:

1.) Kya boss ke aane se pehle ,aap apna work finish kar chuke the ?

     Had you finished your work before the boss came ?

2.) Custom officer ke pas jane se pehle wah ghbra raha tha .

     He was getting nervous before he reached to the custom officer.

3.) Akshay ke Mumbai jane se pehle , wah puri shopping kar chukka tha.

     Akshay had done all shopping before he went to Mumbai.

4.) Jab Ravi school pahunch to Gate keeper Gate band kar chukka tha.

      The Gatekeeper had closed the Gate when Ravi reached School.

5.) Lutere Ajmer me khana kha rahe the jab police Jaipur pahunchi.

      The Robbers were eating in Ajmer when Police reached Jaipur.

                                                       Use of ‘It’:

  1.) Sawa teen baje hai.

        It is quarter past three.

 2.)  Meri watch me paune ek baje hai.

       It is quarter to one by my watch.

 3.)  Thandi  hawa chal rahi hai.

        It is blowing cold.

 4.)  Kya aaj mausam achha nahi hai ?

       Is it not fine weather today ?

5.)  Mujhe bahut dukh hai uske accident ke bare me janker.

      It is sad to me to know about his accident.

 6.) Wahan jane me aadha ghanta lagega.

      It will take half an hour to reach there.

7.)  Peak hours me driving karna bahut bekar hai.

      It is aweful to drive in peak hours.

8.)  Eski sambavna hai ki wah aaj aa sakta hai.

      It is possible that he may come today.

9.)  PVR me movie dekhna bahut badhiya / achha hai.

       It is awesome/ great to watch movie in PVR.

10.) Yah tumhi ho jisne mujhe chup rehne ko kaha hai.

       It is only you who told / asked me to keep quiet.

11.) Uske acche karm hi the jisne use bacha liya.

       It was his good karmas only which saved him.

                                                             Use of ‘There’:

    1.) Car me char log the.

         There were four persons in car.

    2.) Subah khub barish hiu thi.

         There was a lot of rain in the morning.

   3.)  Usko promotion na milne ke kai karan hai.

         There are number of reasons for not granting him promotion.

    4.) Prashant ke reception me 300 se jyada log the.

         There were more than 300 persons in prashant’s wedding reception.

     5.) Kai log hai jo sarkar ki yojnao ka samarthan karte hai.

          There are many people who support government’s policies. 

     6.) Kuch hi virodhi hai.

          There are only few opponents.

     7.) Kuch virodhi hai.

          There are few / some opponents.

    8.) Ghar par koi nahi hoga.

         There will be no one at home

सन्धि (सम् + धि) शब्द का अर्थ है 'मेल' या जोड़। दो निकटवर्ती वर्णों के परस्पर मेल से जो विकार (परिवर्तन) होता है वह संधि कहलाता है। संस्कृत, में परस्पर स्वरो या वर्णों के मेल से उत्पन्न विकार को सन्धि कहते हैं। जैसे - सम् + तोष = संतोष ; देव + इंद्र = देवेंद्र ; भानु + उदय = भानूदय।

सन्धि के भेद

सन्धि तीन प्रकार की होती हैं -

1. स्वर सन्धि (या अच् सन्धि)
2. व्यञ्जन सन्धि { हल संधि }
3. विसर्ग सन्धि

The answer to this question is more about the syntactical meaning of the word 'kernel' than the technical meaning.
There are many theories related to metallic bonding, one of them, called the 'electron sea theory', uses this term: kernel. If we see what kernel means in a non-scientific sense, it refers to the central part of a nut/seed. Using the same reference, we can use it for the metal cations when talking in the context of 'electron sea theory'. This refers to the part of each metal atom except the free electrons. You can call it a 'core' as well, and to some extent, you'd be right.
Now the question which remains is whether or not we can call these parts simply 'cations'. I answer this with another question: Why not? After all, these are (in this context) ions with positive charges, and that's what categorizes them under the definition of the term 'cations'.
I hope that helps.

• Read newspaper daily. 
• Watch youtube videos on news clippings. 
• Download a short 1-minute video. 
• Write the text and try to speak in that manner. 
• Record your voice and listen. 
• Compare it with the newsreader and try to improve. Do a lot of reading. 
• Make a friend with whom you talk in English. 
• Read one article daily for 10 to 15 minutes. 
• Watch youtube for programmes like Toastmasters, Ted Talks.
• Stand in front of the mirror and give a two-minute speech every day.

Follow these tips, and you will observe a significant improvement.

CO is isoelectronic with NO+ and N2. So, options (a) and (b) are the right answers. CO has 14 electrons, 8 from oxygen and 6 from carbon. NO has 15 electrons 8 from oxygen and 7 from nitogen. But, as it becomes NO+, it loses an electron and the number of electrons is 14. Similarly, N2 has 14 electrons, 7 from each of the nitrogen atoms.

Squares of all integers are known as perfect squares. In this lesson, we will discuss a very interesting Mathematical shortcut: How to check whether a number is a perfect square or not. There are some properties of perfect squares which can be used to test if a number is a perfect square or not. They can definitely say if it is not the square. (i.e. Converse is not necessarily true). 

All perfect squares end in 1, 4, 5, 6, 9 or 00 (i.e. Even number of zeros). Therefore, a number that ends in 2, 3, 7 or 8 is not a perfect square. 

For all the numbers ending in 1, 4, 5, 6, & 9 and for numbers ending in even zeros, then remove the zeros at the end of the number and apply following tests:

• Digital roots are 1, 4, 7 or 9. No number can be a perfect square unless its digital root is 1, 4, 7, or 9. You might already be familiar with computing digital roots. (To find digital root of a number, add all its digits. If this sum is more than 9, add the digits of this sum. The single digit obtained at the end is the digital root of the number.)
• If unit digit ends in 5, ten’s digit is always 2.
• If it ends in 6, ten’s digit is always odd (1, 3, 5, 7, and 9) otherwise it is always even. That is if it ends in 1, 4, and 9 the ten’s digit is always even (2, 4, 6, 8, 0).
• If a number is divisible by 4, its square leaves a remainder 0 when divided by 8.
• Square of even number not divisible by 4 leaves remainder 4 while square of an odd number always leaves remainder 1 when divided by 8.
• Total numbers of prime factors of a perfect square are always odd.

4539 ends in 9, digit sum is 3. Therefore, 4539 is not a perfect square.

5776 ends in 6, digit sum is 7. Therefore, 5776 may be a perfect square. 

Step 1: A perfect square never ends in 2, 3, 7 or 8. 

This is the first observation you will make to check if the number is a perfect square or not. For example, consider the example 15623. 

15623

By just noticing the number itself, we can conclude that 15623 cannot be a perfect square. We do not have to go to Step 2.

Step 2: Obtain the digital root of the number: 

How does the digital root of a number would help in determining if a number is a perfect square or not. It turns out; a perfect square will always have a digital root of 0, 1, 4 or 7. 

Take the number 15626 for example. This number ends in digits 6. So it satisfies Step 1. But still we cannot conclude, this number as a perfect square.

Let’s take the digital root of this number. 

1 5 6 2 6 = 5 + 6 = 11 = 1 + 1 = 2

So, the digital root of this number is 2. A perfect square will never have a digital root 2. Hence, we can conclude 15626 is not a perfect square.
Now, there is a rider for this shortcut though, even if both Steps are satisfied, that does not guarantee that the number is a perfect square. 

Let us take up an example here. Consider the number 623461, which is not a perfect square.
Notice that the unit digit is 1. This number could be a perfect square. Let us take the digital root. 

6 2 3 4 6 1

The digital root of 623461 is 4. So it satisfies both Step 1 and 2. Still we cannot conclude that 623461 is a perfect square though.
However, this shortcut comes in really handy to eliminate obvious choices which are not a perfect square to solve competitive examination where you need to find the perfect squares.

Is 14798678562 a perfect square? Is 15763530163289 a perfect square?

Examine both the units digits and the digital roots of perfect squares to help determine whether or not a given number is a perfect square.

As we know a perfect square can only end in a 0, 1, 4, 5, 6, or 9; this should allow us to determine whether the first of our numbers is a perfect square. However, it isn't sufficient to draw a conclusion about the second number. 

Again as we know that if a perfect square ends in 9; it’s tens digit is always even. Alas, even if we do this, it won't rule out numbers ending in 89, because '...89' is a possible square. 

However, as we know no number can be a perfect square unless its digital root is 1, 4, 7, or 9; so, find the digital root of our second number. It’s 5. As 5 isn't in this list, then the number is definitely not a perfect square. 

So, we can conclude, a number cannot be an exact or perfect square if:

-        it ends in 2, 3,7 or 8

-        it terminates in an odd number of zeros

-        its last digit is 6 but its penultimate (tens) digit is even

-        its last digit is not 6 but its penultimate (tens) digit is odd

-        its last digit is 5 but its penultimate (tens) digit is other than 2

-        its last 2 digits are not divisible by 4 if it is even numbe