因为78+45-15+18=（78+18）+（45-15），
所以原题解答错误．
故答案为：错误．
单词拼写：根据句意填入适当形式的词，首字母或中文已给出。
1. The doctor has put me on a low-salt d_______.
2. He is always _______ (抱怨) about anything- his job, his wife and his back.
3. Her father _______ (毕业) from university in 1989 and went abroad.
4. She thought teaching relaxing and easy, but now she finds it very s_______.
5. He uses his _______ (手提的) computer every day.
6. It's a v_______ army from many countries and they ask for no pay.
7. There is still a problem in _______ (紧急的) need of solution.
8. He is busy o_______ an English party.
9. It was g_______ of you to lend me money. Thanks!
10. Just now I _______ (打电话) my friend's number, but the line was busy.
水力活塞泵装置由（）所组成
A.地面部分
B.井下部分
C.抽油杆
D.联系地面井下的中间部分
