— Show me your permit, please.
—Oh, it's not in my pocket. It
| A．might fall out | B．could fall out |
| C．should have fallen out | D．must have fallen out |
----This returned Chinese scholar has become one of the top experts in this field.
----Yes,I know him very well.He____in Africa with animals for eight years.
| A．has worke | B．had worked | C．worked | D．has been working |
----Does Liu Hua serve in the army?
----No,but he ___in the army for three years.
| A．served | B．has served | C．is serving | D．would serve |
The boss praised the young man for his hard work, though he ___ experience.
| A．was lack of | B．was lacking in | C．lacks of | D．was lacking of |
I'll have you _______ English in six months .
| A．speaking | B．speak | C．spoken | D．be able to speak |
I posted the letter some time _____ the week .
| A．in | B．during | C．throughout | D．within |