An(75)service　bus(ESB)　acts　as　a　shared　messaging　layer　for　connecting　applications　and　other　services　throughout　an　enterprise　computing　infrastructure。

单项选择题(74)is a network layer device that supports multiple LAN interfaces and segments LANs into smaller collision and broadcast domains。

单项选择题An(73)statement can perform a calculation and store the result in a variable so that it can be used later。