原理图文件类型后缀名是（），Verilog HDL语言文本文件类型的后缀名是（）。
参考答案：.GDF；.V
急性乳腺炎的主要病因是
A．乳汁淤积
B．产后抵抗力下降
C．细菌侵入
D．不恰当的按摩
E．乳腺受挤压
She is excited to read a note ___ the present from her grandfather. [ ]
A. attaching with
B. attached to
C. attached with
D. attaching to
