颜面部修复手术在瘢痕的早期充血阶段进行,不仅_________,同时术后会产生_____________。
参考答案:手术时出血多;更多的增殖性瘢痕
设F是属性组U上的一组函数依赖,下列叙述正确的是
A.若Y
X,则X→Y为F所逻辑蕴含
B.若X
U,则X→Y为F所逻辑蕴含
C.若X→Y为F所逻辑蕴含,且Z
U,则X→YZ为F所逻辑蕴含
D.若X→Y及Y→Z为F所逻辑蕴含,则X→Z为F所逻辑蕴含
—What were you doing when I rang you this morning?
—I was occupied ______ the housework and kept my son occupied______ his homework.
A.at;doing
B.with;doing
C.at;to do
D.with;to do