In each of the following questions, choose the option that best completes the gap(s). The doctor ____ him to take his medicine regularly.

The sentence "The doctor ______ him to take his medicine regularly" requires the past tense of the verb meaning to give counsel or recommend a course of action. The correct word is advised.

In English, advise (with an "s") is the verb, and advice (with a "c") is the noun. The past tense of the verb "advise" is "advised." The sentence describes a completed action by the doctor, so the past tense is needed.

The other options are wrong for specific reasons:

• "Adviced" is not a valid English word. The noun "advice" does not have a verb form "adviced."
• "Advise" is the present tense/base form and does not match the past-tense context ("The doctor" performing a completed action).
• "Advice" is a noun and cannot function as the main verb of a sentence.

A useful memory aid: the noun "advice" has a "c" (like "ice"), while the verb "advise" has an "s" (like "rise"). Only the verb can be conjugated into past tense.