目前聚合物常用的稳定剂有哪几种?
参考答案:
①甲醛;
②硫脲;
③低分子量的醇类等。
Without the friction (摩擦力) between feet and the ground, people would ______ be able to walk.
A.in no time
B.by all means
C.on any account
D.in no way
Please read the story carefully and try to _____ the answers. [ ]
A. look
B. see
C. look for
D. find out