Lami's father … as a gardener when he was young, but now he is a driver.

Analyze the question

The sentence says Lami's father worked as a gardener when he was young, but now he is a driver. This describes a past habit or situation that is no longer true today. The gap needs a structure that expresses this.

Explain the concept

"Used to + base verb" expresses:

• a past habit or repeated action, or
• a past state that is no longer true.

Examples: She used to live in Kano (but now she doesn't).

Note the spelling. In the positive form it is used to, not "use to". ("Use to" appears only in questions and negatives, such as Did he use to…? or He didn't use to….)

Step-by-step solution

• A. had been working: the past perfect continuous needs another past reference point (e.g., "had been working for years before he changed"). It doesn't fit the contrast with "now".
• B. use to work: wrong spelling and form for a positive statement.
• C. has worked: the present perfect links the past to the present, suggesting he still works as a gardener or has done so up to now. This contradicts "now he is a driver".
• D. used to work: correct. It shows a past occupation that has since changed.

The sentence becomes: "Lami's father used to work as a gardener when he was young, but now he is a driver."

Answer: D

Exam tip: When you see a contrast between "when he was young" and "now", think used to. Also remember that in positive sentences it is "used to" (with a "d"), and "use to" is only for questions and negatives after did.