A 1． B 2． C 3． D 0．

A <img width="151" height="15" src="https://www.beizhujiaoyu.com/uploads/202208/20220503122559_9299.jpg" /> B <img width="84" height="26" src="https://www.beizhujiaoyu.com/uploads/202208/20220503122601_1640.jpg" /> C <img width="84" height="26" src="https://www.beizhujiaoyu.com/uploads/202208/20220503122602_1328.jpg" /> D <img width="92" height="26" src="https://www.beizhujiaoyu.com/uploads/202208/20220503122603_3067.jpg" />

A I<J<K． B J<K<J ． C J<I<K． D J<K<I．

A 若AB=0，则B=O B 对任意矩阵B，总有r(AB)=r(B) C 存在B，使BA=E D 对任意矩阵B，总有r(BA )=r(B)

A 当a=2时，r(A)=1． B 当a=2时，r(A)=2． C 当a≠2时，r(A)=1． D 当a≠2时，r(A)=2．

A <img width="28" height="31" src="https://www.beizhujiaoyu.com/uploads/202208/20220503124434_7566.jpg" /> B <img width="28" height="32" src="https://www.beizhujiaoyu.com/uploads/202208/20220503124435_0067.jpg" /> C <img width="20" height="31" src="https://www.beizhujiaoyu.com/uploads/202208/20220503124436_9129.jpg" /> D <img width="20" height="32" src="https://www.beizhujiaoyu.com/uploads/202208/20220503124437_1630.jpg" />

A <img width="12" height="26" src="https://www.beizhujiaoyu.com/uploads/202208/20220503124019_8036.jpg" /> B <img width="85" height="27" src="https://www.beizhujiaoyu.com/uploads/202208/20220503124021_3398.jpg" /> C <img width="32" height="26" src="https://www.beizhujiaoyu.com/uploads/202208/20220503124021_8818.jpg" /> D <img width="55" height="28" src="https://www.beizhujiaoyu.com/uploads/202208/20220503124023_4131.jpg" />

A t(n)． B t(n-1)． C t(2n)． D t(2n-2)．

A 1-φ(1．5)． B 1-φ(0．5)． C 1-φ(1．96)． D 1-φ(1)．