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刷刷题刷刷变学霸
举一反三
【单选题】Text 2 We recently sailed with our research ship through the Red Sea to the Indian Ocean where we did research work for about a year. Our main objectives (目标) were the little-known Maldi...
A.
the coral reef exists in regions with warm climate
B.
the coral reef provides favorable living conditions for them
C.
the creatures are away from the danger of being eaten by sharks
D.
most sea creatures feed on the colourful coral
【单选题】TB/T2658.21-2007标准规定，当用双探头法探测铝热焊焊缝时，应对焊缝全宽度进行连续扫查或分段扫查。分段扫查宜从焊缝两侧进行，也可从同侧进行，每段宽度一般不应大于（）。
A.
10mm
B.
15mm
C.
20mm
D.
25mm