问题
选择题
Shopping on line can provide ____ convenience and choice, but not ____ websites are safe enough for shopping.
A．either; both
B．neither; any
C．both; both
D．both; all
答案
答案：D
第一空用both，构成 both...and ，用来连接两个宾语"既方便，种类又多"；第二空用all 与not连用，表示部分否定，"并非所有的网站都安全"，此处无两者之意。