问题
选择题
Which of the two cameras are you going to buy?
—I’ll buy of them，so I can give one to my friend．
A．all
B．both
C．neither
D．either
答案
答案：B
both 二者全都；all 三者或三者以上全都；either 二者择一；neither 二者皆不。根据句中“the two cameras”和“I can give one to my friend．”知，应用both.
cosωt
