“I called you yesterday. A woman answered, but I didn’t recognize her voice.” “Oh, it _____ my aunt Jean.”
| A．must be | B．must have been | C．might be | D．can have been |
It’s a difficult skill to master, but ______, it will benefit you for the rest of your life.
| A．once obtained | B．when to obtain |
| C．after obtaining | D．while obtaining |
My grandmother has kept the photo ______ she can see it every day for a couple of decades.
| A．which | B．when | C．that | D．where |
Bob is in a hopeless situation, ______ we will keep a very close eye on.
| A．which | B．where | C．that | D．when |
In the past decades, sea ice ______ in the Arctic as a result of global warming.
| A．had melted | B．has been melting | C．melted | D．is melting |
I know you don’t like her, but try not to make it so ______.
| A．curious | B．obvious | C．various | D．previous |