Gilbert wasn’t ______ the time this morning, so he was late for school.
| A．involved in | B．particular about | C．linked to | D．aware of |
How the fire in the dancing hall started _________ a mystery.
| A．to remain | B．remains |
| C．is remaining | D．is remained |
Please don’t try to back out _____ everything has been arranged.
| A．until | B．though | C．when | D．unless |
Simon is very regretful. If he had been more careful, he _____ such a big mistake.
| A．hasn’t made | B．hadn’t made |
| C．won’t have made | D．wouldn’t have made |
______ by jeep, we visited a number of cities in South China.
| A．Traveling | B．Traveled |
| C．To be traveling | D．Having traveled |
Zheng He had over 300 ships, _______ some were over 150 meters long and could carry up to 1,000 people.
| A．that | B．which | C．of which | D．on which |