With the word "PM2.5"______ heard and seen in our life, people become more and more concerned about air pollution.
| A．constantly | B．occasionally | C．consequently | D．contemporarily |
I called ________ his house this morning, but he wasn’t in. So I left a message telling him I would call______ him the next day.
| A．on; on | B．at; at | C．at; on | D．on; at |
The man _______you played a trick is from Canada.
| A．to whom | B．at whom | C．on whom | D．whom |
—Are you coming to the Christmas party?
—I’m not sure. I_____ go to the concert instead.
| A．must | B．would | C．should | D．might |
Is it _________ Tom often plays computer games ________ makes you angry？
| A．that, that | B．Which, which | C．that, which | D．which, that |
__________ many times, he still couldn't understand it.
| A．Having told | B．Though he had been told |
| C．He had been told | D．Been told |