模板中相邻两块板的高低差允许值为（）。
A.Y1
B.2
C.2.5
D.3
参考答案：B
—Tony, you must have noticed the student who broke the window.
—I’m sorry. I _______ attentively.
A．studied
B．was studying
C．am studying
D．would study
赵女士，52岁，因患宫颈癌需行子宫切除术。
病人出现上述表现的原因是
A．过敏体质B．抵抗力差C．药液污染D．毒性反应E．剂量过大
