A:CO
B:CO2
C:H2
D:N2
写出几个与礼貌有关的词语
____ ____ ____ ____
看图片,写单词,将句子补充完整
She had fish and____.
2.75+3.8+1.25=3.8+(____+____) 45.89-18.8-11.2=45.89-(____+____)