肉眼血尿是指每升尿内含血量超过
A．1mlB．2mlC．3mlD．4mlE．5ml

The girl on the bus began to sing a pop song and soon all the others ______.
A．joinedB．joined inC．attendedD．took part in

骨髓()
A.只位于长骨的骨髓腔内B.黄骨髓有造血功能C.胎儿和幼儿骨内完全是红骨髓D.黄骨髓不能转化为红骨髓E.红骨髓无造血功能

She is always the first ______to school.
A. comingB. to comeC. to have comeD. having come

The underlined word "scam" in Paragraph 4 is closest in meaning to______.
A．jokeB．gameC．kidnapD．cheat

既能按气相型循环，又能按沉积型循环的元素是__________。