I still remember_____ to visit the Mountain Tai when I was young and I am longing to visit it again.

A．to take

B．to be taken

C．taking

D．being taken

DNA双螺旋结构中的碱基以氢键相连配对，总是（）。

A．A与A，G与G

B．G与T， A与C

C．A与T，G与C

D．A与G， T与C

E．T与T，C与C