The little boy sat ________to his father and listened ________with great interest.
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.
Read the comics every day and _______ the ones that remind you of your life. Post them on the refrigerator or anywhere else you can see them frequently.
The participants were encouraged to _______ others in the class to do the project, and the entire team would get credit.