He is careless a student that he often some letters while writing.
A. such; leaves on
B. so; leaves off
C. so; leaves out
D. such; leaves out
网友回答
A. such; leaves on
B. so; leaves off
(答案→)C. so; leaves out
D. such; leaves out
解析：考查so,such用法和固定词组。So+adj+a/an+单数名词=such a/an adj+单数名词。本题中的so careless a student=such s careless student.如此粗心的学生。Leave out遗漏；leave off停止做某事，戒除…句意：他是一个如此粗心的学生以至于他在写作的时候介词遗漏一些字母。故C正确。