——Would you like to go bike riding with us?
——Sorry. I am afraid I can't. I have ___________ homework to do.
A:a little
B:a lot
C:a few
D:a lot of
解方程: x+1 + 2x−5 =1.
胆固醇、小分子脂肪酸、维生素D等物质以简单扩散的方式优先通过细胞膜,这是因为( )
按拼音写汉字
chāo piào____ xuàn yào____ chú fáng____