Tom _____ his English book in his backpack. [ ]
A. looks
B. looks like
C. puts
D. meets
答案:C
山顶洞人仍用打制石器,但已掌握___________ 和___________ 技术,他们能走到很远地方同别的原始人群_____________ 生活用品。
形训有哪些局限性?