---Please come here again. -----I will surely ____ you when I come to your city someday. A. drop in at B.drop in C.drop on D. drop in on 答案:D 解析: drop in on +人 意为:顺便走访某人; drop in at+地方 意思是:顺便走访某地方。如图,小明为了测量一铁塔的高度CD,他先在A处测得塔顶C的仰角为30°,再向塔的方向直行40米到达B处,又测得塔顶C的仰角为60°,请你帮助小明计算出这座铁塔的高度.(小明的身高忽略不计,结果精确到0.1米,参考数据:,,)