摘要： have to but now. I have to study. have to意为“必须 侧重于客观上的必要. 其句型为have (has) to+动词原形 如:We have to leave now. He has to work on Sunday. I had to do my homework last Sunday.
It's a 1 Sunday morning．Some good friends are going 2 a field trip to the Yellow Mountain．They are going to 3 a picnic on the top of the mountain．Every-one takes some food and drink 4 them． 5 two hours later, they are all tired and thirsty．They have to stop 6 a rest and drink．Then they go on 7 ．They have a lot of problems 8 to the top．Linda often goes the 9 way, Hill trips over a stone(石头), Sam has to tie his shoes, Ed can't 10 his heavy bag, Lucy hikes too slowly．But they help each other, and at last they get to the top．They have a nice lunch and a good time．
It's a 1 day．We are 2 a field trip to the Yellow Mountain．We are 3 a picnic on the top of the mountain．We take some food and drinks 4 us． 5 two hours later, we are all tired and thirsty．We have to stop 6 a rest and drink．Then we go on 7 ．We have a 8 problems getting to the top．Wang Xiang often goes the wrong way．Du Tao 9 to tie his shoes．Haohao can't 10 his heavy bag．Meimei hikes too slowly．But we help each other, and at last we get to the top．We have a nice lunch and a good time．
Do you hope to move to another city or a foreign country?It may be interesting．But how about moving to 1 planet?A US company now has a plan：sending people to Mars 2 20 years．
To begin with,the company plans to send 3 people to go to Mars first．It will 4 them several months to get there．When they arrive,they will build a 5 first．
But Mars is not an easy place to 6 ．It is rocky,cold and has lots of sandstorms(沙尘暴)．Also,there is 7 air for breath．So people would have to live in a special house．They would have to 8 special clothes if they go out．
People will have to find 9 resources(资源),iron,water and so on．All these could help people live there…
Sounds interesting?You might want to go to Mars now． 10 will things go well as the company hopes?We'll wait and see．