Find out the synonym of the underlined word from the options below:

When you see your teacher approaching you, a slight wave to attract his attentionis appropriate.

If something _______ your attention or your eye, you notice it or become interested in it.

There was a _______ tremble in her voice, which showed that she was very nervous at that time.

It is _______ not to say "Thank you" when you are given something.

In many cultures, people signify their agreement by _______ their head.

Our teacher often said, "Who knows the answer? _______ your hand.”

They started, as _________gatherings but they have become increasingly formalized in the last few years.

The lecturer explained the problem very clearly and is always _______ in response to questions.