The computer,        help we human beings have stepped into the information age, should be regarded as one of the most important inventions in the 20^th century.

A．which

B．whose

C．with its

D．with whose

关于内分泌系统的最佳描述是( )

A．都通过下丘脑-腺垂体-内分泌腺(细胞)-激素系统的反馈调节
B．由内分泌腺及全身内分泌细胞组成的信息传递系统
C．无导管，分泌物直接进入血液的腺体
D．分泌物通过体液传递信息的系统
E．区别于外分泌腺的系统