Wechat（微信）really influences people's life．
．It is easier for us to keep in touch with others．（ ）
A．MainlyB．ExactlyC．SimplyD．Mostly
We have worked so long．Shall we stop ______ a rest？（ ）
A．haveB．to havingC．havingD．to have
Rules are helpful to us，______ we have to follow them．（ ）
A．soB．butC．orD．because
Tim is going to give his father a surprise ______ Father's Day．（ ）
A．inB．atC．onD．by
Ladies and gentlemen，attention please!I have ______ important to tell you．（ ）
A．nothingB．somethingC．everythingD．anything
I like hiking in the forest because the air is pretty ______．（ ）
A．freeB．dirtyC．pollutedD．fresh