The workers were working from 7:00 a.m. to 7:00 p.m. that day, only ____ once at noon to have their lunch.
| A．to stop | B．stopping |
| C．to have stopped | D．having stopped |
The police said they would not give up looking into other possibilities ____they find out what happened.
| A．as | B．while | C．until | D．although |
When Justin didn’t ____ for lunch the next day, Mrs Foster became worried and called the police.
| A．give up | B．show up | C．make up | D．stay up |
If ____ in, the viruses can result in illness or even deaths.
| A．breathed | B．to breathe | C．breathes | D．is breathed |
Standing inside ____ lots of strange creatures with white skin and large black eyes.
| A．was | B．is | C．were | D．be |
—I have been waiting for you so long.
—Sorry, I have been in the library, _______ my friend look for some books.
| A．helped | B．helping | C．to help | D．help |