未知题型 ___________ it or not, his discovery has created a stir in scientific circles.A) Believe B) To believeC) Believing D) Believed

未知题型 ______ one time, Manchester was the home of the most productive cotton mills in the world.A) On B) ByC) At D) Of

未知题型 If only the committee _________ the regulations and put them into effect as soon as possible.A) approve B) will approveC) can approve D) would approve