【单选题】下列表示热轧带肋钢筋的强度等级符号的是( )
【简答题】Grey whales have long been ________ in the north Atlantic and hunting was an important cause for that. A) extinct B) extinguished C) detained D) deprived
【判断题】钢筋符号HRB400表示的意思是:普通轧热带肋钢筋强度级别为400MPa。
【单选题】Grey whales have long been __________ in the north Atlantic and hunting was an important cause for that.
【判断题】钢筋符号HRBF335表示的意思是:有抗震性能的普通热轧带肋钢筋强度级别为335MPa。
【判断题】在配线子系统电)缆线既可以用对绞电缆也可以用光缆。
【简答题】Every year thousands of grey whales make the longest migration of any animal, traveling 7,000 miles each way between the Arctic and Baja, California. The grey whales spend the long summer days in thei...
【单选题】Many species of whales will not breed unless ______.
A.
they are in the same group for a long term
B.
they are isolated from other species
C.
they are in the company of many other whales
D.
there are enough genes available