If a drug that is already on the market has the potential to help adults and children who have the same disease, or if it is widely used in children and the absence of labeling seems dangerous, the FDA can require that the drug undergo prediatric study.
b) that the drug undergoes
c) that the drug is to undergo
d) the drug undergoing
e) the drug to have to undergo
ans: a
我不太了解that之後的第3人動詞到底該不該加s
還是說require that是有特別
誰可以解釋一下嗎?