Experiments of this kind ___in both the U.S and Europe well before the Second World War.
| A．had conducted | B．have conducted | C．have been conducted | D．had been conducted |
_____ into English, the sentence was found to have an entirely different word order.
| A．Translating | B．To translate | C．Having translated | D．translated |
He was obliged to ______ the trade of shoemaker.
| A．take on | B．take in | C．take up | D．take down |
The government of the United States began at once to investigate the case ______ a lot of students were killed.
| A．that | B．when | C．where | D．why |
---I probably shouldn’t have any more cake.
---Oh, ______. It won’t kill you.
| A．go ahead | B．hold on, please | C．you’re welcome | D．that will do |
It is ten years since the scientist ______ on his life’s work of discovering the valuable chemical.
| A．made for | B．set out | C．took off | D．turned up |