Flow control is a function that prevents network congestion by ensuring that (1) do not overwhelm (2) with data. There are three commonly used methods for handling network congestion. (3) is used by network devices to temporarily store bursts of excess data in memory until they can be processed. (4) are used by receiving devices to help prevent their buffers from overflowing. (5) is a flow -control scheme in which the source device requires an acknowledgment from the destination after a certain number of packets have been transmitted.

1（）

A．transmitting devices

B．transmitted devices

C．receiving devices

D．received devices

免疫检验中的"床边"试验指（）

A.免疫比浊

B.乳胶凝集

C.定性ELISA

D.胶体金免疫层析

E.免疫印迹