磨损现象是非常复杂的,是导致机械损坏的主要原因之一。
参考答案:对
阅读Sam上周活的短文,根据短文内容选择正确答案。
On Monday, Sam played football. On Tuesday, Sam listened to music. OnWednesday, he watched TV. On Thursday, he helped his mother with the housework. On Friday, he washed his clothes. On Saturday,
he did his homework. On Sunday, he played the guitar.
1. On Saturday, Sam .
A. talked to his friends
B. did his homework
2. On Monday, Sam _ .
A. played football
B. played basketball
3. On Friday, Sam .
A. read a book
B. washed his clothes
4. On Sunday, Sam _ .
A. played the guitar
B. played on the computer
5. On Wednesday, Sam .
A. listened to music
B. watched TV
原文:All this suggested ancient harmonies. 译文:这一切建议了古代的和谐气氛。 改译: