I have offered to paint the house________a week's accommodation.
A:in exchange for
B:with regard to
C:by means of
D:in place of
关于人口增长、资源、环境污染相关关系的叙述正确的是
已知数列{an}为等比数列,满足a4+a7=2,a2•a9=﹣8,则a1+a13的值为( )
读世界局部板块分布示意图,完成下列问题.