—I phoned you yesterday morning. A girl answered, but I didn’t recognize the voice.
—Oh, it ________ my younger sister. She was in my room at that moment.
A.must have been B.should have been
C.could have been D.may have been
In the reading room, we found her ________ at a desk, with her attention ________ on a book.
A.sitting; fixing B.to sit; fixed
C.seating; fixing D.seated; fixed
(2016 ·浙江)Had the governments and scientists not worked together, AIDS-related deaths ________ since their highest in 2005.
A.had not fallen B.would not fall
C.did not fall D.would not have fallen
Bless your heart, I know you didn’t break the vase ________. Don’t cry！
A.on purpose B.by accident
C.on business D.by mistake
—Monitor?
—I’m not monitor of our class. I ________ with the teacher until the monitor is elected.
A.will just help B.am just to help
C.am just helping D.have just helped
The new buyer identified a dozen new sources for the material, ________ proved to be reliable.
A.most of them B.most of which C.most whom D.most of those
