题目

“No swimming！” means that ________.A. we can swim B. it's safe to swimC. better swim D. don't swim 答案：【答案】D【解析】“No swimming!”的意思是“禁止游泳！”A. we can swim我们会游泳；B. it's safe to swim游泳是安全的；C. better swim最好游泳；D. don't swim不要游泳。故答案为D。下图所示的是北半球的一段纬线，M、N两点分别是某日的晨线、昏线与该纬线的交点。一年中M、N两点有重合于O点的现象，一年中，O点的太阳高度最大值约为(　　)A．23° B．43°C．47° D．57°