----______ girl over there is your cousin?
----The slim one_______ a mask on her face.
| A．Which; has | B．Whose; wears |
| C．Which; with | D．Who; wearing |
—You can hardly imagine the pleasure of chatting with friends on Wechat (微信).
—Really? But it ______ cause you much trouble if someone get your personal information.
| A．may | B．must | C．need | D．should |
_________, when Marx was already ________, he began to learn Russian.
| A．In 1870s; in his fifties | B．In 1870s; in fifties |
| C．In the 1870s; in his fifties | D．In the1870s; in fifties |
He made a serious mistake, but he took action to change that _________ it got worse.
| A．until | B．when | C．because | D．before |
We should try our best to make ______ world that is safer, cleaner and healthier than ____ one we are living in now.
| A．the; / | B．a; / | C．the; the | D．a ;the |
—Hey, Tom. Let's go swimming.
—Just a moment. I______ a message.
| A．send | B．sent |
| C．am sending | D．have sent |