— ________?

— He is very clever.[ ]

A. Who is the boy

B. What does the boy do

C. What's the boy like

D. What does the boy do

受电弓在升弓时静态接触压力的最佳值和允许偏差是（）。

A、80N±10

B、70N±10

C、80N±5

D、70N±5