题干
The road was covered with sand ________ the heavy sandstorm.
A：because of
B：because
C：for
D：as
答案(点此获取答案解析）
A
The road was covered with sand ________ the heavy sandstorm.
A：because of
B：because
C：for
D：as
(
)满足
且
时，
,
，则函数
在区间
内零点的个数为
