We can hardly believe such a young boy ______ travel around the world all by himself.
| A．may | B．need | C．should | D．must |
These wild flowers are so special I would do _______ I can to save them.
| A．whatever | B．that | C．which | D．whichever |
Parents are taught to understand _______ important education is to their children’s future.
| A．that | B．how | C．such | D．so |
We cannot figure out _______ quite a number of insects, birds, and animals are dying out.
| A．that | B．as | C．why | D．when |
Is this the reason _______ at the meeting for his carelessness in his work?
| A．he explained |
| B．what he explained |
| C．how he explained |
| D．why he explained |
_______ puzzles me most is that I don’t know _______ the difference between those two lies.
| A．What; that | B．It; that | C．What; where | D．It; where |