og 101

Even though the direct costs of malpractice disputes amounts to a sum lower than one percent of the $541 billion the nation spent on health care last year, doctors say fear of lawsuits plays a major role in health-care inflation.

(A) amounts to a sum lower

(B) amounts to less

(C) amounted to less

(D) amounted to lower（C）

(E) amounted to a lower sum

关于last year的修饰问题：even though last year...这样就知道last year 是修饰整个分句，但是放在分句句末我觉得会产生修饰the nation spent on health care 的歧异？
这样的话，若B项 改成：amout to less.就不知道该选B还是C？

牛牛指教！

同问。

The correct choice must feature a verb that agrees with the plural noun costs and refers to an action completed last year (past tense).

OG 认为 last year 是修饰整个句子的。

我觉得从意思上理解是（今年）比去年的541 billlion少了1%，那整个句子应该只能用和主句一致的现在时啊？哪位NN指点一下啊，拜托了。