British scientists have produced _____ they believe is the world's smallest Christmas card．
| A．which | B．who | C．that | D．what |
What _____ pity that you couldn't be there to receive prize!
| A．a; a |
| B．the;a |
| C．a;the |
| D．the;the |
Experiments of this kind ______in both the U. S. and Europe well before the Second World War.
| A．have conducted |
| B．have been conducted |
| C．had conducted |
| D．had been conducted |
I wasn't sure if he was really interested or if he ______ polite.
| A．was just being |
| B．will just be |
| C．had just been |
| D．would just be |
The manager is said to have arrived back from Paris where he ______ some Europeanbusiness partners.
| A．would meet |
| B．is meeting |
| C．meets |
| D．had met |
After Jack had sent some e-mails, he______ working on his project. (2012 .山东)
| A．had started |
| B．has started |
| C．started |
| D．starts |