[单项选择]

The "main storage" normally means that part of internal storage into which instructions and other data must be loaded for subsequent execution or processing. In large computing systems, the term "main storage" is (71) to "memory". "Buffer" mainly indicates a special-purpose storage or storage area allowing, through (72) storage, the data transfer between two functional units having different transfer characteristics. A buffer storage is used between non-synchronized devices or where one is (73) and the other is parallel or between those having different trans far rates. " (74) (memory)" is also a special-purpose buffer storage, smaller and faster than main storage, used to hold a copy of instructions and data obtained from main storage and likely to be needed next by the processor. "Register" is commonly composed of a part of internal storage having a specified storage (75) and
A. instant
B. temporary
C. timely
D. transient

The "main storage" normally means that part of internal storage into which instructions and other data must be loaded for subsequent execution or processing. In large computing systems, the term "main storage" is (71) to "memory". "Buffer" mainly indicates a special-purpose storage or storage area allowing, through (72) storage, the data transfer between two functional units having different transfer characteristics. A buffer storage is used between non-synchronized devices or where one is (73) and the other is parallel or between those having different trans far rates. " (74) (memory)" is also a special-purpose buffer storage, smaller and faster than main storage, used to hold a copy of instructions and data obtained from main storage and likely to be needed next by the processor. "Register" is commonly composed of a part of internal storage having a specified storage (75) and
A. suitable
B. optional
C. choice
D. preferred

Niagara is an Indian word which means "roaring water". Indeed, the roar of the falling water of Niagara can be heard (1) a distance of 5 kms. Imagine (2) of water flowing over a cliff 90 feet high and you will get an idea of that terrible noise. And (3) tremendous power the Niagara River has! It moves big rocks about and throws them into the boiling water below. (4) ago an old ship without single person on board was put in mid-stream. It sailed down the river (5) a toy boat with great speed. Having reached the fall, the ship dropped into the boiling water, never (6) again. There were some people who wanted to become famous (7) swimming across the most dangerous part of the Niagara River. One of them was Captain Webb who said that he would try to swim cross the Niagara, which (8) crowds of people. On the evening of July 1^st, 1893, Captain Webb came up to the river and (9) a plunge
A. toappear
B. appearing
C. appeared
D. appear