“x不小于4且不大于7”,用不等式表示是______.
根据题意,得4≤x≤7,
故答案为:4≤x≤7.
Such problems as high blood pressure and heart trouble are _________ features of old age.
A.universal
B.complete
C.specific
D.absolute
现浇混凝土结构常出现哪些质量外观缺陷( )。
A.露筋
B.蜂窝和孔洞
C.夹渣
D.疏松或裂缝