It is he , rather than I, that in the company for two years.
A:works
B:work
C:has worked
D:have worked
把分式2x-y2x+y中的x、y都扩大到原来的4倍,则分式的值( )
下面是五年级二班第二小组女生的体重记录,求出她们的平均体重____千克.(得数保留一位小数)
中生代又称为“爬行动物时代”.(判断对错)
(Ⅰ)求证:平面ABE⊥平面EOD;
(Ⅱ)求平面ECD与平面ABE所成的锐二面角的大小.