I want to be a volunteer some day. I feel _____ is my duty to help others.
| A．this | B．that | C．them | D．it |
—Has Billy finished his homework today?
—I have no idea.Heit this morning.
| A．would do | B．was doing | C．has done | D．had done |
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 |