当环境温度低于-20℃时,不得对HRB335、HRB400的钢筋进行冷弯加工。
参考答案:对
【生物——现代生物科技专题】
科学家通过诱导黑鼠体细胞去分化获得诱导性多能干细胞(iPS),继而利用iPS细胞培育出与黑鼠遗传特性相同的克隆鼠,流程如下:
图中重组囊胚通过()技术移入白鼠子宫内继续发育,暂不移入的胚胎可使用()方法保存。
Great changes have taken place in that village. It is no longer ____ it was 10 years ago, ____ it was so poor.
A.what; when
B.that; which
C.what; which
D.which; that