题目

“大旱生蝗灾”，每逢旱情加重，往往伴随着蝗虫的肆虐。蝗虫体表防止体内水分散失的结构是 ( ) A . 甲 B . 鳞片 C . 外骨骼 D . 毛 答案：C—Could you tell me ________ of the river is? —It’s about 4,000 kilometers. A．what the length B．how the length C．how long D．the length