一、单项选择( ) 1. Teenagers have to be 18 years old before they ____to drive a car.A.are allowed B.allowedC.will be allowed D.allow( ) 2. As China grows stronger and stronger, Chinese ____in more and more schools out of our country. A.teaches B.is taughtC.has taught D.was taught( ) 3. —Your bedroom is so clean.—Of course.It ________every day.A.cleans B.cleanedC.is cleaned D.was cleaned( ) 4. It's not your turn yet.Please wait on the chair over there until you__________.A.are calling B.have calledC.are called( ) 5. Hangzhou ____as the City of Silk.Tourists like shopping for silk there.A.knows B.is knownC.was known D.will be known( ) 6.—Why does the earth look blue in space?—Because most of the earth's surface ______ by water.A.covers B.is coveredC.cover D.are covered( ) 7.Students do less homework now.Usually it ______ before 9 o'clock in the evening.A.finishes B.finishedC.is finished D.was finished( ) 8.—Your classroom is so clean.—Of course.It _______ every day.A.is cleaned B.was cleanedC.cleans D.cleaned ( ) 9.A lot of trees __ |