题目

数列是各项为负数的等比数列，若，则公比q的取值范围是（ ）A. B.C. D. 答案：【答案】D【解析】由已知得数列的首项，公比，根据，两边同时除以，得，解不等式结合已知条件可知公比q的取值范围.因为数列是各项为负数的等比数列，则首项，公比，即，两边同时除以，得，即，解得或（舍去）故公比q的取值范围是，故选：D.It wasn’t until he came back _____ he knew the police were looking for him.A．whenB．thatC．sinceD．before