在观察热靶时发现制冷电流有较大跳变，这与下面哪一个部件无关（）。
A.温控板
B.探头
C.测温板
D.探头电缆
参考答案：C
He is generally considered _________the first computer. [ ]
A. to have invented
B. inventing
C. to invent
D. having invented
分度头在使用时应该注意哪些事项？
