The teacher couldn’t make himself       attention to because the students were so noisy.

A．to pay

B．to be paid

C．paid

D．pay

一般500kV变压器差动保护用TA选用TPY型已可满足要求，如果要考虑外接输电线采用快速自动重合闸装置，TPZ型将有更好的技术经济性能。