图形上未注出公差的尺寸,可以认为是没有公差的尺寸。
A. 对
B. 错
Icebergs are parts of glaciers that break off, ________ into water, foat about awhile, and finally melt.
A. mobile
B. drift
C. shift
D. rotate
Streams of fire ran down the hills, and at length a _________ arose so loftily that it touched the skies.
A. fire
B. spark
C. glow
D. blaze
In the Persian Gulf area, oil is found in ______and its production has been able to keep up with world demand.
A. elaboration
B. abundance
C. elegance
D. efficiency