急性喉阻塞临床特点以________为主，伴有________和________，多数还伴有________。
参考答案：吸气性呼吸困难｜喉鸣｜三凹征｜声嘶
He doesn’t feel________because he has ________friends.
A．happily; a few
B．happy; a few
C．happily; few
D．happy; few
试述超基性岩石主要岩石类型及成矿专属性。
