已经在某一型别(如737-300)飞机上作为副驾驶的机组成员需经（）才能成为机长
A、升级训练A
暂无解析
我国农业社会主义改造基本完成的标志是 ______。
Attendance at football matches have _____ since the coming of television.
机体应付紧急情况的神经系统机构是
Human behavior is mostly a product of learning ________ the behavior of animals dependsmainly on instinct.
Be careful, _______ you'll fall down.
