Digital cameras are becoming very popular, though some still ________ too much.
A. pay B. cost C. spend
—Would you mind my using your computer? —______
| A．Yes. Here you are. | B．No, you can’t. |
| C．No, not at all. | D．You’re welcome. |
I wonder __________ achieve a balance between my schoolwork and my hobbies.
| A．how can I | B．how I can |
| C．what can I | D．what I can |
Mother wants to spend some time chatting with me _________ she is very busy every day.
| A．and | B．or | C．but | D．so |
Our teacher often asks us _________ questions in groups.
| A．discuss | B．discussed |
| C．discussing | D．to discuss |
In a green school, everyone agrees to be _______ about the environment.
| A．careful | B．honest |
| C．nervous | D．rude |