The teacher asked a very difficult question. It was Ted who finally _____ a good answer.
A:came up with
B:had raised
C:went through with
D:put up with
商鞅变法中推行下图所示标准器具的主要目的是?
关于青春期的心理烦恼,认识正确的是( )
①是一种不正常的现象 ②是我们生理发育和心理变化过程中的正常现象
③是一种“成长的烦恼” ④会引发孤独、郁闷、焦躁等消极情绪
如图所示,是锡的熔化和凝固的图象,根据图象回答:
下列有关人类生殖和发育的叙述,错误的是( )
用图1所示的装置探究摩擦力跟压力大小的关系.