题目

题型：同步题难度：来源：

基本语法。1. The streets here _____ (clean) by the cleaners every morning.
2. These flowers _____ (water) once every three days.
3. Many new things _____ (invent) by the scientists in the 20th century.
4. Yesterday a composition on protecting animals _____ ( write) by the students of our class.
5. The little girl had learned to play the piano  _____ the age of five.

答案

1. are cleaned   2. are watered   3. were invented   4. was written  5. at