合理的营养不仅能够增进健康，而且也是（）、（）的有效手段。
参考答案：防治疾病；延年益寿
A boy with two dogs ____ when the earthquake rocked the city.[ ]
A. were sleeping
B. is asleep
C. was sleeping
D. are asleep
对大虾经行加工，首先先将大虾洗净，剪去（）、虾须等部位，然后修整虾尾
A.虾枪
B.虾爪
C.虾头
D.虾尾
