今年暑假报名参加奥数培训的学生有242名,至少有几名学生是在同一个月份出生的?
242÷12=20…2(人),
20+1=21(人);
答:至少有21名同学是同一个月出生.
With the word“PM2.5"_____ appearing in media reports,people pay greater attention to it and seek health tips for smoggy days.
A.constantly
B.instantly
C.rarely
D.directly
为保证安全,在给焊炬点火时,最好先开氧气,点燃后再开乙炔。