根据词首字母和汉语提示完成单词。
1. The woman has studied English s _____ 1990.
2. —Have you heard a _____ Lei Feng?
—Yes, of course.
3. The plane has a _____ in Tianjin already.
4. In fact, since 1988 _____ (工程) Hope has built schools all over China.
5. How long has Lingling _____ (认识) Sally?
1. since 2. about 3. arrived 4. Project 5. known