At the Copenhagen conference, all the countries were called on to do all they could to control greenhouse gas emissions it was too late.
| A．when | B．after | C．until | D．before |
______ the blind wandering through the traffic, motorists would have to step on their brakes at once.
| A．Seeing | B．Having seen | C． Seen | D．To have seen |
Much of life today _____ the manners of everyday getting along: queuing, answering the phone, keeping promises, remembering birthdays.
| A．is | B．are | C．was | D．were |
After the snowstorm, mailboxes in the community were covered by snow, or _______, or lying on the ground.
| A．breaking | B．being broken | C．having broken | D．broken |
He has been talented at designing and creating things ________ he was young.
| A．when | B．before | C．since | D．while |
I set up email addresses for connecting with my parents last May. But I didn’t write to them as often as I ______.
| A．should | B．must have | C．should have | D．must |