A．onB．upC．overD．upon

【C6】A．onB．forwardC．overD．together

We can surely overcome all difficulties that may come up.A.get onB.come overC.get overD.c

【C16】A．awayB．upC．overD．off

The maths teacher is the only one she looks （).A、forB、upC、up toD、upon

He is______an important customer now and he will be back tonight.A．calling onB．calling upC

【C18】A．onB．inC．overD．of