1 . Many lessons are now available online, from _____ students can choose for free.

A．whose

B．which

C．when

D．whom

2 . They decide to have more workers for the project ____ it won’t be delayed.

A．even if

B．as if

C．now that

D．so that

3 . 【2018·江苏】_______ you can sleep well, you will lose the ability to focus, plan and stay motivated after one or two nights.

A．Once	B．Unless
C．If	D．When

4 . It sounds like something is wrong with the car’s engine. ________, we’d better take it to the garage immediately.

A．Otherwise	B．If not
C．But for that	D．If so

5 . It is so cold that you can’t go outside ________ fully covered in thick clothes.

A．if	B．unless
C．once	D．when

6 . Lessons can be learned to face the future, ________ history cannot be changed.

A．though

B．as

C．since

D．unless

7 . _______unemployment and crime are high, it can be assumed that the latter is due to the former.

A．Before

B．Where

C．Unless

D．Until