光的反射定律是什么？

A. 制动器主动盘
B. 制动鼓
C. 制动蹄
D. 制动器从动盘

A. DHCP Discover-DHCP Offer-DHCP Request-DHCP Ack
B. DHCP Request-DHCP Ack-DHCP Discover-DHCP Offer
C. DHCP Request-DHCP Offer-DHCP Discover-DHCP Ack
DHCP Discover-DHCP Ack-DHCP Request-DHCP Offer