At the meeting an important problem _______ and it attracted everyone’s attention.

I want to ________ the secrets of nature and apply them for the happiness of man.

You were _______ to take your shoes off when you entered the school lab, but you didn’t.

It took the scientists seven days to________Takla Makan________“the sea of death”.

In our childhood, we were often ________ by Grandma to pay attention to our table manners.