以下哪种物质对成骨细胞的作用与其浓度有关()
A.白细胞介素
B.成纤维细胞生长因子
C.前列腺素
D.集落刺激因子
E.以上都不是
参考答案:C
—I’m very tired these days because of studying for physics.
—Why not ______ music. It can make you _______.
A.listen to; relaxing
B.to listen to; to relax
C.listening to; relax
D.listen to; relaxed
以下生物的受精作用在体外进行的是 [ ]
A.蜻蜓
B.蟾蜍
C.蝗虫
D.家蚕