单项选择题

The most versatile ______ embryonic stem cells, which ______ found in the embryo at the earliest stage of development and can grow into any part of the body.

A．are, are
B．is, is
C．are, is
D．is, are
<上一题 目录 下一题>
热门 试题

单项选择题
He said the most unusual aspect of the Mexican trial was that the 12 teenagers were not given any drags to suppress their immune systems, ______ would normally destroy any cells from other animals.
A．at which
B．which
C．to which
D．as
单项选择题
There ought to be less anxiety over the perceived risk of getting cancer than ______ in the pub lie today.
A．exists
B．exist
C．existing
D．existed
相关试题