各项均为正数的数列{a_n},{b_n}满足：a_n+2=2a_n+1+a_n,b_n+2=b_n+1+2b_n，($n\in N^{*}$)，那么（    ）

“人间四月芳菲尽，山寺桃花始盛开”，造成这一差异的环境因素是（  ）

按要求变化下列各句
(1)Lisa was on duty yesterday afternoon. （对划线部分提问）
____  was on duty yesterday afternoon?
(2) The students had a piano lesson last Monday. （改为否定句）
The students ____  a piano lesson last Monday.
(3) Claudia was at the culture club this morning. （改为一般疑问句）
____ at the culture club this morning?
(4) It’s Friday today. （对划线部分提问）
____  is it today?
(5)They were at the office yesterday. （对划线部分提问）
____  they yesterday?