单项选择题
One day while Mr. King was working, he had a(an)（）and his left leg was badly injured.
A.business B.accident C.matter D.event
单项选择题 It is assumed that students at an intermediate level will have a good（）of the basic structures and vocabulary of English.
单项选择题 I am pleased to take（）to exchange views with you.
单项选择题 Please leave the key under the door（）you go out.
