HIV与感染细胞膜上cD4分子结合的病毒刺突是（）

A.gp120

B.gp41

C.P24

D.P17

E.gp160

May Day holiday is coming. My family are discussing w   1    to do for it. We are planning to travel a  2     . We want to go to Singapore because my dad has g    3  to Singapore for a meeting. He has b   4   there  twice. It’s a nice and clean c 5     . We will f   6   there next Monday. It will  t__7___ us about two hours to go  there  by  air. The weather there is very good all year r    8  . We will visit many p  9     of interest in Singapore .  I think  we  will  be  happy  t 10      the whole trip.