问题
选择题
--Everyone wants to keep healthy without too much effort.
--So let's start from our mouth by _______ those healthy foods, which people can easily get in their daily life.
A．buying
B．cooking
C． eating
D．throwing
答案
答案：C
by是介词后跟名词,代词或动名词，吃东西应用动词eat或have.