题干
选出划线部分有错的一项。
It | is difficult | for the children | to find | interesting something | to do in the building. |
A | B | C | D |
答案(点此获取答案解析）
D
的光滑斜面上，当细绳由水平方向逐渐向上偏移时，细绳上的拉力将 ( )
