His sister left home in 1998, and_______ ever since.
| A．had not been heard of | B．has not been heard of |
| C．had not heard of | D．has not heard of |
It is the third time that he ____ abroad on business this year.
| A．goes | B．went | C．has gone | D．go |
Thousands of works of art, ________ the most famous paintings, were ________ during the war.
| A．included; missed | B．including; missing |
| C．included; missing | D．including; missed |
Here is the girl _________ school bag has been stolen.
| A．who | B．whom | C．whose | D．which |
He was about to tell me the matter _______someone stopped him
| A．as | B．while | C．when | D．until |
______improve his oral English, he took part in the summer course
| A．So as to | B．In order to | C．So that | D．In order that |