29. The computer system _______ suddenly while he was searching for information on the Internet.
| A．broke down | B．broke out | C．broke up | D．broke in |
_____ he stayed in England , he visited some of his friends.
| A．When | B．During | C．For | D．In |
You two follow me; the rest _____ where you are.
| A．stays | B．lay | C．stay | D．stayed |
Dear Jenny, thank you for your letter which ______ on April 1st.
| A．arrived | B．arrived at | C．arriving | D．arrived me |
_________, they delivered the message as quickly as they could.
| A．Arriving at | B．On arriving | C．When arriving | D．Arrived |
I do believe that ______ swim across the river, but, in that situation, I ____ do that.
| A．am able; couldn’t | B．could; was able to |
| C．was quite able to; couldn’t | D．couldn’t was able to |