4.Researchers haven't found out what has.... in the pollution of the river.
A.caused
B.made
C.resulted
15.Mai said she....a programme about Jupiter then.
A.was watching
B.watched
C.had watched
16.I have won the gold medal. -..........
A.Well done
B.I don’t understand
C.That’s awful
18.A:Our house was destroyed by the storm B:...........
A.Wow
B.That’s a relief
C.That’s awful