The twins were so much alike that we had great trouble ________one from the other.
| A．distinguishing | B．to distinguish |
| C．distinguish | D．distinguished |
--- ___it rain tomorrow， we would have put off the visit to the Yangpu Bridge.
| A．Were | B．Should | C．Would | D．Will |
He is the only one of the students who _________ a winner of scholarship for 3 years.
| A．is | B．are | C．have been | D．has been |
Parents ____ bring up their children under 16 and educate them properly.
| A．could | B．may | C．might | D．ought to |
All of us found _____ necessary to learn a foreign language.
| A．this | B．that | C．it | D．what |
I used to _____ bed at nine. Now I am used to ____ bed at ten.
| A．go, going | B．go to, going to | C．go to, go to | D．going to, going to |