合成聚合物压裂液不属于水基压裂液。（）
参考答案：错
解析：合成聚合物压裂液是水基压裂液稠化剂的一种类型，所以合成聚合物压裂液也属于水基压裂液。
Qian Xuesen is a great Chinese scientist ______ great contributions (贡献) to building our motherland. [ ]
A. which has made
B. which have made
C. who has made
D. who have made
备课环节是上好课的先决条件，备课时教师应把全部精力放在钻研教材上。( )
