Unit 4 When was it invented? (同步练习题)一、单项选择( )1. The bridge_ by the local people in 2000Abuilt Bwas built Cbuild Dwas build( )2. More sheep_ by the farmer since two months ago Awas sold Bwere sold Chas been sold Dhave been sold( )3. Keys_ used for _ the doors. A. is, opening B. is, opened C. are, opening D. are opened( )4. My teacher told me that my homework must_ on time.Afinish Bbe finish Cb
