菜粉蝶的发育过程是( )。
A:卵 →若虫 →成虫
B:卵 →成虫
C:卵 →幼虫 →蛹 →成虫
D:卵 →蛹 →成虫
— It's very kind _____ you _____ help me complete the difficult job.
— You're welcome.
一束光在空气中经凸透镜折射后,下列说法中正确的是