The students were ________ over the ________ problem，listening to the teacher with a ________ expression on their faces.
| A．puzzled；puzzling；puzzling | B．puzzled；puzzling；puzzled |
| C．puzzling；puzzling；puzzled | D．puzzling；puzzled；puzzling |
Don’t touch anything __________ your teacher tells you to.
| A．if | B．though | C．unless | D．even though |
Would you mind not ________ about me ?
| A．worry | B．worrying | C．worried | D．to worry |
All of us were ________ at the __________ news.
| A．frustrating, frustrating | B．frustrating, frustrated |
| C．frustrated, frustrating | D．frustrated, frustrated |
He is afraid of ___________ strangers.
| A．see | B．seeing | C．saw | D．seen |
--- He went to see the man who was in hospital yesterday.
--- ____________.
| A．So did he | B．So he did | C．He did so | D．Did so he |