In public places, we can often see ______ that tell us useful things, such as no parking, no smoking, etc.

It is very important for English teachers to have a knowledge of the theories of language_______. 

 I bought a new type of cell-phone, which was the ____ of all my classmates.

But the unpleasant feeling of coldness disappeared at the _______ of his students pouring out of their classroom to give him a warm, wordless welcome.

Desipt the fact that there was a big ______ over the meeting, it seemed that a good many of the invited guests would still attend it.