—What's the matter with the man hanging his head there?
—Well，if you ________ know, he was caught stealing my bike.
| A．must | B．may | C．can | D．shall |
You can arrive in Beijing earlier for the meeting __ you don’t mind taking the night train.
| A．provided | B．unless | C．though | D．until |
The old woman has loved Tom _____ he were her son.
| A．because | B．as | C．if | D．as though |
She heard a terrible noise, ___brought her heart into her mouth.
| A．it | B．which | C．this | D．that |
They agreed to rent the house ______ the roof should be repaired.
| A．on condition that | B．as soon as | C．when | D．unless |
The reason ___he didn’t come was ____he was injured.
| A．that, because | B．why, that | C．why, because | D．that, that |