1.stem cell n.干细胞

Her right-to-life convictions extend to stem cell research, which she opposes.
她还反对干细胞研究，以表现她那泛滥的”生存权“信念。

Long-term follow-up after allogeneic hematopoietic stem cell transplantation.
异基因造血干细胞移植后的长期随访。

2.clinical trial 临床试验

Now a larger clinical trial is under way.
目前一较大规模的临床试验正在进行中。

It plans soon to start a late-stage clinical trial of a drug for lung cancer.
辉瑞计划马上开始对一种肺癌药物的最后阶段的临床试验。

3.respond to 回应,反应

Never respond to requests for personal or account information online ( or over the phone).
绝对不要响应那些在线要你提供个人或账户信息的请求（或通过电话的这类请求）。

A spokesman didn't respond to requests for comment.
该公司一位发言人没有回应记者的置评请求。

4.remain to 保持

Some evident problems remain to be sorted out.
仍有些突出问题亟待解决。

And the most important questions remain to be answered.
而最重要的问题仍然没有答案。