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. |