An (71) service bus (ESB) acts as a shared messaging layer for connecting applications and other services throughout an enterprise computing infrastructure. It supplements its core (72) messaging backbone with intelligent tansformation and routing to ensure that messages are passed (73) . Services participate in the ESB using either Web Services messaging standards (74) the Java Message Service. ESBs are increasingly seen by users and analysts as core components in (75) IT.
（73）处填（）。
A．relying
B．rely
C．reliably
D．reliable