有关双气囊三腔管的护理，正确的是（）。

A.插入三腔管后先向食管气囊注气

B.置管期间唾液可随时咽下

C.胃气囊注气量为100～150ml，食管气囊注气量为200～300ml

D.放置48h后，出血停止，放气观察12h后无出血再拔管

E.拔管前从胃管内注石蜡油20～30ml

A basic premise of OGSA is that everything is (71) by a service: a network enabled entity that (72) some capability through the exchange of messages. Computational resources, storage resources, networks, programs, databases, and so forth are all (73) . This adoption of a uniform service-oriented model means that all components of the environment are virtual. More specifically, OGSA represents everything as a Grid service: a Web service that conforms (74) a set of conventions and supports standard interfaces for such purposes as lifetime management. This core set of consistent interfaces, from which all Grid services are implemented, (75) the construction of hierarchical, higher-order services that can be treated in a uniform way across layers of abstraction.

（72）处填（）。

A．provides

B．have

C．expands

D．limits