如图,在一次数学课外实践活动中,小聪在距离旗杆10m的A处测得旗杆顶端B的仰角为60°,测角仪高AD为1m,则旗杆高BC为____m(结果保留根号).
商店里原来有40台电视机,卖掉29台,还剩____台?又运来30台,现在商店里有____台电视机?
_______ hard work it is! I can't do it by myself.