在进行性肌营养不良症患者发病中起主导作用的因素为_________即病理基因所引起的一系列酶及生化改变。
参考答案:遗传因素
氯化钠样品中混有少量碳酸钠,某学生欲用下面两种方法进行提纯.
方法一:样品溶于蒸馏水,加稍过量盐酸,蒸干溶液.
方法二:样品溶于蒸馏水,加稍过量石灰水,过滤,向滤液中加稍过量盐酸,蒸干溶液.
你认为这两种方法中______不合适,理由是______.
用 when或 while填空。
1. I was looking out of the window _________ the teacher asked me.
2. What is he doing _________ his parents came back?
3. Mike was playing games _________ Jack was studying.
4. I was about to fall asleep _________ the baby began to cry.