检测蛋白用可见光分光光度计，波长用（）。
A.400nm
B.380nm
C.300nm
D.280nm
E.250nm
参考答案：D
叙述在施工缝处继续浇筑混凝土的规定。
Tom didn't go hiking with his classmates ____ his illness. [ ]
A. because
B. because of
C. as
D. since
