20.
如图,在△ABC和△DEF中,已知∠BCA=∠EFD,∠B=∠E,要判定这两个三角形全等,还需要条件( )
| A. | ∠A=∠D | B. | AB=FD | C. | AC=ED | D. | AF=CD |
18.
反比例函数y=$\frac{k}{x}$的图象如图所示,则k的值可能是( )
0 279508 279516 279522 279526 279532 279534 279538 279544 279546 279552 279558 279562 279564 279568 279574 279576 279582 279586 279588 279592 279594 279598 279600 279602 279603 279604 279606 279607 279608 279610 279612 279616 279618 279622 279624 279628 279634 279636 279642 279646 279648 279652 279658 279664 279666 279672 279676 279678 279684 279688 279694 279702 366461
| A. | $\frac{1}{2}$ | B. | 1 | C. | 2 | D. | -1 |