等比数列{an}的前n项和为Sn,已知S1,2S2,3S3成等差数列,则{an}的公比为____
Things can go wrong when people work under s____ (pressure).
我国古代《易经》一书中记载,远古时期,人们通过在绳子上打结来记录数量,即“结绳计数”.如图,一位母亲在从右到左依次排列的绳子上打结,满七进一,用来记录孩子自出生后的天数,由图可知,孩子自出生后的天数是( )
xún zhǎo
quán shuǐ
zhōng yú
cǎi zhāi
____
tú huà
jiǎn dān
huí yì
zuò wèi