15. Lam (not do) ______hasnt done_________ his homework yet.
16. Low energy light bulbs (use)______wont be use _____ in the future.
17. Two years ago, he (teach) _____taugh_____ at a village school.
18. Ngan (sometimes, have) ______sometimes has_________ many fascinating ideas
15. Lam had not done his homework yet.
16. Low energy light bulbs will use in the future.
17. Two years ago, he taught at a village school.
18. Ngan sometimes has many fascinating ideas.
15- hasn't done (Present perfect - yet)
16- will be used (Future - passive voice)
17- taught (Past simple - ago)
18- has (Present simple - sometimes)