题干
is good for our health.
A：To eat healthy food
B：Eat health food
C：Eating healthy food
D：Eats healthy food
答案(点此获取答案解析）
C
is good for our health.
A：To eat healthy food
B：Eat health food
C：Eating healthy food
D：Eats healthy food
；以D为起点，其余顶点为终点的向量分别为
.若
分别为
的最小值、最大值，其中
,
,则