In order not to be disturbed ,I spent three days __________ in my study.
| A．locking | B．locked | C．to lock | D．lock |
_____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 |
--- How come your father can read books in German?
--- Well, he____on a project with some German engineers for 3 years when he was young.
| A．worked | B．was working | C．had worked | D．would work |
It was reported that 115 miners__________ in the flooded mine for eight days were pulled out alive at last.
| A．trapped | B．being trapped | C．were trapped | D．had trapped |
--- 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 |
Not until they left school________how much their teachers loved them and helped them.
| A．they realized | B．did they realized |
| C．the would realized | D．had they realized |