葡萄状肉瘤属于()
A．血管肉瘤
B．脂肪肉瘤
C．纤维肉瘤
D．横纹肌肉瘤
E．纤维肉瘤
参考答案：D
--- Let’s go to play football, shall we?
--- Sorry, I can’t. I must go over the points the teacher explained ______ I forget them.
A．after
B．when
C．before
D．since
