因式分解
(1)x(x+4)+3
(2)x2-2x+1-y2.
(1)原式=x2+4x+3
=(x+1)(x+3);
(2)原式=(x-1)2-y2
=(x+y-1)(x-y-1).
His failure ______ great disappointments to his parents.
A.forced
B.caused
C.made
D.provided
病人患的是右中心型肺癌,头颈面部出现肿涨,上胸部出现静脉怒张。这说明肿瘤侵犯和压迫,或者转移淋巴结压迫在何部位()
A、非主动脉
B、肺静脉
C、颈静脉
D、上腔静脉
E、锁骨上静脉