用括号内所给动词的适当形式填空。
{#blank#}1{#/blank#} In the past three years, my home town ______________(change) a lot. already.
{#blank#}2{#/blank#} It's hard to say what ____________ (happen) in 100 years in our country.
{#blank#}3{#/blank#} They_______________(not travel)to Shanghai next week, are they?
{#blank#}4{#/blank#} The students________(chat) from 6 to7 yesterday evening.
{#blank#}5{#/blank#} When I got to the station yesterday morning, my friends _______(wait ) for me at the entrance.
{#blank#}6{#/blank#} If it__________ (not rain) tomorrow, we'll go hiking.
{#blank#}7{#/blank#} He____________ (not write) a letter to his mother yet. He has to do that soon. His mother misses him very much.
{#blank#}8{#/blank#} Would you please__________(not make) such a big noise. The baby is sleeping.
{#blank#}9{#/blank#} It's a long time since we ________(meet) last time, isn't it?
{#blank#}10{#/blank#} ——How many times _______the girl __________(forget) to take the keys to her home?——At least three times.
{#blank#}11{#/blank#} You must spend as much time as you can ________  (practise) playing the piano.
{#blank#}12{#/blank#} They_______(live) in Wuxi since they were born.

    This is a street crossing. There are red and green lights at each corner. Drivers must watch the lights carefully.
    When there is a green light, the cars may go. When there is a red light, the cars must stop. They must wait until the red light changes to green. Then they can go on. Sometimes the cars want to make a right turn or a left turn. They can make a right turn when the light is green or red. But they must wait until the green light is shining if they want to turn left.
    Some people are color-blind(色盲). They can not tell the difference(不同) between the red and green lights. These people must not drive, or there will be accidents. We must keep our streets safe.