As we all know．____life is hard for any of us. If we live___ happy life，we must all work harder.
| A．／：／ | B．／；a | C．a；／ | D．a；a |
When first to the market, these products enjoyed great success.
| A．introducing | B．introduced | C．to introduce | D．being introduced |
There is cooking oil left in the house. Would you go and get .
| A．little...any | B．little...some | C．a little...any | D．a little...some |
--I haven’t heard from John for a long time.
--What do you suppose to him?
| A．was happening | B．to happen |
| C．has happened | D．had happened |
The reporter said that the UFO east to west when he saw it.
| A．was traveling | B．traveled |
| C．had been traveling | D．was to travel |
Many countries are increasing their use of natural gas, wind and other forms of .
| A．energy | B．source | C．power | D．material |