You had better … your assignment now.

Analyze the question: The sentence is "You had better ...... your assignment now." The question tests the structure had better, a modal-like expression used for advice or warnings.

Explain the concept: "Had better" is followed by the bare infinitive, which is the base form of the verb without "to".

Structure: had better + base verb

Examples:

• You had better leave now.
• She had better study hard for JAMB.
• We had better go before it rains.

Even though "had" looks like past tense, "had better" refers to the present or future. It works like a modal verb (can, should, must), and modals are always followed by the base form.

Solution, testing each option:

• A. "You had better did": wrong, because the past tense cannot follow "had better".
• B. "You had better done": wrong, because the past participle is not used here.
• C. "You had better doing": wrong, because the -ing form is not used after "had better".
• D. "You had better do your assignment now": correct, because it uses the bare infinitive.

Answer: The complete sentence is: *"You had better do your assignment now.

Exam tip: Whenever you see "had better", "would rather", or any modal (can, could, will, would, shall, should, may, might, must), choose the base form of the verb. Don't be fooled by the word "had" into picking a past form.