Doctors hope that one day the body’s master cells, called stem cells, can be directed to grow in organs or tissues appropriate for transplant, use them to test drugs and potentially toxic chemicals, and may study them to gain insight into basic human biology.
A. transplant, use them to test drugs and potentially toxic chemicals, and may study them
B. transplant, using them to test drugs and potentially toxic chemicals, and studied
C. transplant, used to test drugs and potentially toxic chemicals, and studied
D. a transplant, use them for testing drugs and potentially toxic chemicals, and for studying
E. a transplant, used to test drugs and potentially toxic chemicals, and may study them
请NN给我讲下这道题吧,还有C中的 used的逻辑主语是谁呢?transplant?还是cells 我怎么觉得怪怪的 这道题没有理解意思。。 |