+GIẢI THÍCH+
8. Neither his father nor his mother plays / play plays mahjong.
9. Neither parent is / are is fond of playing mahjong.
10. None of my friends was / were was there.
11. Many a student has / have has made the same mistake.
12. Gold, as well as platinum, has / have has recently risen in price.
13. The boss, as well as his colleagues, has / have has been robbed by the robber.
14. Ten tons is / are is a heavy load.
15. Fifty miles is / are is a long distance.
16. Thirty years is / are is a long time.
17. One of the books has / have has been missing.
18. The poor is / are are suffering.
19. You should decide which one of the three choices A, B, or C best answers / answer answers the question
.20. One of the most intelligent students who scores / score score full marks is / areis John.
21. The only one of these most intelligent students who is / are is under 18 is / are is Peter.
22. One of these most intelligent students whose example is / are is  being followed is / areis John.