24. He is very about his chance of winning a scholarship this semester.A. optionalB. obvi

问题补充：

24. He is very about his chance of winning a scholarship this semester.

A. optional

B. obvious

C. optimistic

D. conventional

答案：

A. optional

B. obvious

C. optimistic

D. conventional

解析：本题考查形容词。Optional选修的；obvious显然地；conventional传统的。 be optimistic about sth. “对……持乐观态度”。句意：他对他这学期获得奖学金的机会非常乐观。