The doctor asked him not to leave his wound __________.
| A．expose | B．exposed | C．to expose | D．exposing |
—May I smoke here ?
—If you ____, choose a seat in the smoking section.
| A．should | B．could | C．may | D．must |
This cake is very sweet. You _____ a lot of sugar in it.
| A．should put | B．could have put | C．might put | D．must have put |
— The woman biologist stayed in Africa studying wild animals for 13 years before she returned.
— Oh, dear ! She ______ a lot of difficulties !
| A．may go through | B．might go through |
| C．ought to have gone through | D．must have gone through |
Helen ______ go on the trip with us, but she isn’t quite sure yet.
| A．shall | B．must | C．may | D．can |
The World Wide Web is sometimes jokingly called the World Wide Wait because it ______ be very slow.
| A．should | B．must | C．will | D．can |