A:are using, have added
B:is used, are adding
C:are being used, have been added
D:being used, were added
选出下列画线部分发音不同的一项.
①A. teacher B. head C. eat ____
②A. pear B. bear C. near ____
解方程组或解不等式组
(1)x+13-y+24=0x-34-y-33=112; (2)2x-13-5x+12≤15x-1<3x+1.