多项选择题在我们工厂化栽培蝴蝶兰时，所用的基质主要成分为（ ）。 A、水苔 B、树皮 C、黏土 D、壤土 E、沙土
单项选择题The landing flare is executed during a critical phase of flight and, except for auto-land operations, is dependent upon the judgement, skill and experience of the pilot.
