用“there is,there are,there are't,there wasn't,there were,there weren't”填空（急!）
(急!)
1、________a lot of boats fifty years ago.But_______ a pier here.
2、Now__________many people and cars here.
3、30 years ago,_________a lot of people,factories or a subway here.
4、Now__________bridges,highways and ferries here.But 50 years ago__________a ferry pier and some bridges here.
5、50 years ago,_________a tunnel,a highway or a subway.