It’s hot ____________summer in Beijing.
| A．by | B．on | C．at | D．in |
It’s a beautiful，sunny day! There ________ many people here on vacation.
| A．be | B．am | C．is | D．are |
Don’t be afraid of asking for information ______it is needed.
| A．when | B．after | C．although | D．unless |
There great changes in our city in the past 10 years.
| A．were | B．had | C．have been | D．have had |
Hurry up!The play for ten minutes.
| A．has begun | B．began | C．has been on | D．has been |