肠外营养液的输入途径主要是中心静脉和周围静脉。
参考答案：对
Physics ______ more interesting than maths. Do you think so? [ ]
A. are
B. is
C. was
D. were
一般认为宫颈长度≤多少厘米，则为宫颈功能不全（）
A.2cm
B.3cm
C.4cm
D.5cm
E.6cm
