— I heard the phone ringing in the office next door.
— You _______ it. They haven’t got a phone yet.
| A．couldn’t hear | B．couldn’t have heard | C．didn’t hear | D．wouldn’t have heard |
________passenger plane crashed near Gazvin, Iran and all 168 people on________board were killed.
| A．A; a | B．A; / | C．The; the | D．The; a |
--How often do you drop your English teacher a line?
---________. But usually once a week.
| A．As usual | B．It depends | C．Generally speaking | D．Have no idea |
Some English scientists are identifying problems ____ technology in the 21st century. If solved, the solutions could change the world.
| A．facing | B．faced | C．being faced | D．having faced |
Exactly ____they did when at last they reached the sea remains a complete mystery.
| A．that | B．how | C．which | D．what |
One thing’s for sure, the fire _____by some cigarette butts.
| A．might cause | B．could have caused |
| C．must have been caused | D．should be caused |