题目

When he realized the police had seen him, the man _____the exit as quickly as possible. A. made up      B. made for   C. made out      D. made off 答案：B 解析: make for…表示“向某地走去”；make off 后常接介词，表示“从……跑掉”；make out 有“看出；理解；开(收据等)；进展；装出”等含义；make up有“编造；和解；弥补；化装；构成”等含义。如图所示，a、b两点相距24m，一列简谐波沿a、b所在的直线传播．t=0时，a点处于波峰、b点处于波谷；t=0.5s时，a点处于波谷、b点处于波峰．下列判断正确的是（ ）A．波一定是由a向b传播的B．周期可能是0.4sC．波长可能是16mD．波速一定是48m/s