We have been in the school ______ three years ago and Mrs. Lee Has taught us English_______ three years.
A：since; since
B：for; since
C：since; for
D：for; for
生物多样性不包括（ ）
下列物质中属于天然高分子化合物的是（ ）
下列句子中划线成语或俗语使用有误的一项是（ ）
