-- I'd like to invite you to a party tomorrow evening.
-- Thank you, but ______ I'll be free I'm uncertain.
| A．while | B．if | C．when | D．whether |
It is a rule in his family that __________ comes home earlier should cook the dinner for the family.
| A．anybody | B．who | C．who that | D．whoever |
The black horse is___________ of the pair.
| A．the strongest | B．the stronger |
| C．the strong | D．quite strong |
I coutdn't have got to the meeting on time____________ an earlier train.
| A．if I had not caught | B．unless I had caugh |
| C．if ! did not catch | D．unless I caugh |
________ is quite natural,a beginner can't read the books written in English very quickly.
| A．Which | B．As | C．What | D．It |
__________ it rain, the crops_____________.
| A．Shall,would be saved | B．Should, would be saved |
| C．Would, should be safe | D．Were, might be safe |