在同一个圆里,直径的长度是半径的( ),可以表示为d=( ),或r=( )。
2倍;2r;
— Do you have enough to ______ all your daily expenses?
— Oh yes, enough and to spare. [ ]
A. cover
B. spend
C. fill
D. offer
相同物质的量的下列有机物,充分燃烧,消耗氧气的量相同的是[ ]
A.C3H4和C2H5
B.C3H6和C3H8O
C.C3H6O2和C3H8O
D.C3H8O和C4H8O2