纳米材料的表面粒子占总粒子的比例极大，这是它有许多特殊性质的原因。假设某氯化钠纳米颗粒的大小和形状与氯化钠晶胞的大小和形状相同，则这种纳米颗粒的表面粒子数与总粒子数的比值为（ ）
It's said that Tina will go to Canada by herself．
Yes． of her parents will go with her．（ ）
A．BothB．NeitherC．Either
If buildings fall down with people inside，the snake robots can help ____people under the buildings．（ ）
A．take upB．look forC．cut up
Have you ever to Caozhou Peony Garden？ Yes，I there last year．（ ）
A．been；wentB．gone；wentC．been； gone
China is almost as as the US，and it is the country in Asia．（ ）
A．big；biggerB．big；biggest
C．bigger；biggest
Look! This restaurant is always crowded．
The food here ______be very delicious． Let's go and have a taste．（ ）
A．needB．can'tC．must
粤公网安备 44130202000953号