人们“只知其母,不知其父”的情况出现在( )
A:母系氏族社会
B:早期猿人时期
C:父系氏族社会
D:晚期猿人时期
补写出下列名篇名句中的空缺部分。
①元嘉草草,____,____。(辛弃疾《永遇乐·京口北固亭怀古》)
②顾吾念之,____,徒以吾两人在也。(司马迁《廉颇蔺相如列传》)
③____,献愁供恨,____。(辛弃疾《水龙吟·登建康赏心亭》)
完形填空。
I 1 a bad cold yesterday. So I didn’t go to school 2 morning. After breakfast, I 3 a book. There’re many signs 4 it. From this book I know 5 about traffic(交通). We should walk or drive on the 6 of the road(路)and get slower(慢下来)at the crossing of the roa D. “Red light”means“ 7”. “Green light”means” 8”. We 9 go in the time of “Red light”. We must 10 the“Green light”and go.
关于力对物体做功的叙述,下列说法中正确的是( )