After getting lost in a storm, a member of the navy team ______ four days later.
It was not until 1938 _________ the first colour TV programme was broadcast.
You can borrow my car ________ you promise not to drive too fast.
We were told not to touch the equipment in the laboratory unless ________.
If you cannot have a good command of grammar as well as precise usage of each word you’ve learnt, it is ________ for you to use English flexibly.
A new study of HIV-infected people in Haiti indicates that starting treatment early could save many patients who might _______ die of AIDS.