Next semester, Susan must take three compulsory courses.

[单选题]You must take good care of the drainage cock of the air control systemBecause （） leads scale formed which might malfunction the pilot control valve and other instruments.A . the temperatureB . the rustC . the pressureD . the humidity

[单选题]You must take good care of the drainage cock of the air control system. Because lead scale formed which might malfunctions the pilot control valve and other instruments.A．the temperatureB．the rustC．the pressureD．the humidity

[单选题]Must I take a taxi? - No, you ________ . You can take my car.A.had better t

[问答题]We must take somemeasures to control the pollution.

[单选题]Normally a student must attend a certain number of courses in order to grad

[单选题]Normally a student must attend a certain number of courses in order to grad

[单选题]Normally a student must attend a certain number of courses in order to grad

[单选题]Normally a student must attend a certain number of courses in order to grad

[单选题]Normally a student must attend a certain number of courses in order to grad

[单选题]Must I take a taxi? No, you _______. You can take a car.A.had better to.B.d