If you want to ________ a pleasant visit, find out as much as possible about the manners and customs of your host country.
| A．ensure | B．deserve | C．secure | D．serve |
Scientists have found no ________of life on Mars so far,though great efforts have made on the research.
| A．symbols | B．signs | C．marks | D．signals |
A lot of people were made tired of the lecture which ________as long as four hours.
| A．kept | B．went on | C．continued | D．lasted |
I have to amuse myself by looking after my 10－month baby since I have nothing important to work________these days.
| A．in | B．during | C．on | D．for |
It took the scientists seven days to________Takla Makan________“the sea of death”.
| A．climb;calling | B．through;called |
| C．across;naming | D．cross;named |
—Where did ________traffic accident happen,sir?
—It took place at ________crossroads by the bank.
| A．a;/ | B．the;a | C．/;a | D．a;a |