以下哪项不是法洛四联症引起的畸形
A．室间隔缺损
B．主动脉骑跨
C．房间隔缺损
D．肺动脉狭窄
E．右心室肥厚
参考答案：C
设正项等比数列{an}的前n项和为Sn，且a4=8，S4-S1=38，则数列{an}的公比等于______．
按要求转换下列句式。
1. Lucy usually cleans the cage every two days. (对画线部分提问)
_____ _____ _____ Lucy usually clean the cage?
2. Jack's grandfather doesn't know how he should use a computer. (改为简单句)
Jack's grandfather doesn't know how _____ _____ a computer.
