Colours can change our moods and make us happy or sad .

He used to ______ problems ______ English, but he can speak English very well now.

Dogs have a very good ______ of smell and are often used to search for survivors in the earthquake.

Cloning plants is straightforward while cloning animals is _____________ more complicated

Isn’t that Ann’s husband over there?—No, it ______ be him-I’m sure he doesn’t wear glasses.