A:C2H4 C4H8
B:CH4 C3H8
C:CH4 C5H10
D:CH3COOH C2H6
B: During the first days of the Spring Festival holiday, pollution levels aren't ____ ____ ____ they were last year.
甲班:168 167 170 165 168 166 171 168 167 170
乙班:165 167 169 170 165 168 170 171 168 167
用高倍显微镜观察洋葱根尖细胞的有丝分裂,下列描述正确的是( )
东—____ 少—____ 出—____
左—____ 堂—____ 关—____