新树脂颜色越深,说明其()
A.含杂质越多
B.化学性质越差
C.物理性能越差
D.交联剂加入量较少
参考答案:A
She was born ______ a warm spring morning. [ ]
A. in
B. on
C. at
D. for
构成母体的基本*位或元素称为()。