Not until the early years of the 19th century ________ what heat was.
| A．man did know | B．did man knew |
| C．didn't man know | D．did man know |
_________a written permission, he had to write another letter to the president of the university.
| A．Not giving | B．Not having been given |
| C．Having not given | D．Having not been given |
--- Have you heard that Jones, along with her parents,_______to Hainan for the winter vacation?
--- Really? No wonder I haven’t seen her these days.
| A．had been | B．have been | C．has gone | D．have gone |
There’s growing unrest among the poor and unemployed. The media points out that it’s the government that should have a lot to ________.
| A．answer for | B．stand for | C．go for | D．care for |
The traffic problems we are looking forward to seeing_____have attracted the government's attention．
| A．solving | B．solve | C．solved | D．to solve |
—Have you seen your aunt lately?
—Yes, in fact I saw her yesterday．I_________ her for several months．
| A．haven’t seen | B．didn’t see | C．hadn’t seen | D．don’t see |