Don’t leave the water ______ while you brush your teeth.
.– Jack, when shall we go to visit Mr. Smith? – It’s up to him. We’ll go to see him whenever _______.
.He spoke very slowly, but he still didn’t get his meaning _______.
.----I’m going downtown. ----Come on, _______.
.This bag is twice ______ weight of that one. You’d better carry ______ lighter one of the two.
.A clean environment can help the city bid for the Olympics, which ______ will promote its economic development.