胚胎性肿瘤是
A．癌B．肉瘤C．母细胞瘤D．精原细胞瘤E．霍奇金淋巴瘤
参考答案：D
I ________ for Beijing next Saturday. Do you know when the earliest plane ________ on Saturday?
A．am leaving; takes off
B．Leave; takes off
C．leave; is taking off
D．am leaving; is taking off
湿蒸汽发生器管道的连接方法有哪些？
