小明五次测试成绩如下：91，89，88，90，92．则这五次测试成绩的平均数是（ ），方差是（ ）。
90；2
女性，45岁，因绞窄性肠梗阻行急诊手术，发病前曾饱食。
对该病人首选的麻醉方式是（）
A.全身麻醉
B.硬膜外麻醉
C.蛛网膜下腔阻滞麻醉
D.颈丛神经阻滞
E.臂丛神经阻滞
The old woman_________sit in front of the house,__________for her son to come back from
the front. [ ]
A. was going to ; waited
B. would ; waited
C. was going to ; waited
D. would ; waiting
