题目

So far this year we________ a fall in house prices by between 5 percent and 10 percent. A . saw B . see C . had seen D . have seen 答案：D下列营养物质中，能为人体生命活动提供能量的是（  ）①糖类   ②脂肪   ③蛋白质   ④水    ⑤无机盐A.①③⑤      B.①②④      C.①②③      D.①②⑤