Without the earth’s atmosphere to protect them, astronauts can be exposed to intense radiation from the sun, ____ them at risk of cancer.
| A．to leave | B．leaving | C．having left | D．left |
Lucy couldn’t remember when she met Tom, but she was sure it was on ______Monday when she had ______ music class.
| A．/; the | B．the; / | C．a; a | D．/; a |
I ______ an old letter while I was searching my drawer.
| A．came up | B．came across | C．came on | D．came about |
Before taking the photo ,_______ the focus of the camera.
| A．adopt | B．adjust | C．adapt | D．check |
They were making a plan to help those students _____, which attracted me.
| A．in brief | B．in public | C．in action | D．in need |
We didn’t know you were in trouble at that time,_____ we would have given you a hand.
| A．therefore | B．however | C．otherwise | D．though |