A:mgv
B:mgvsinθ
C:mgvcosθ
D:mgvtanθ
将下列句子改为被动语态(1)I sent a letter to you last month.____(2) Do we use it for cooking?____(3) Where did you build the bridge?____(4) Mother tells me a story every day.____(5) Can he finish his homework on time?____
①7月0℃等温线②800mm年等降水量线 ③热带与亚热带的分界线④湿润地区与半湿润地区的分界线