对《大自然的语言》第③段文字运用的说明方法分析正确的一项是( )。
A:下定义、举例子,从古代到近代,从起源到发展,说明什么是物候和物候学及有关知识。
B:下定义、列数字,用数字说话,增强说服力,突出说明语言的准确。
C:作比较、举例子,把物候与物候学进行比较,突出了物候学由古代演变而来的历史。
D:列数字、作比较,说明了物候对农业的重要性,体现了作者严谨趵工作作风。
When ________ different cultures, we often pay attention only to the differences without noticing the many similarities.( )
①保持不变;②一直减小;③先增大后减小;④一直增大;⑤先减小后增大
Hi,I'm Betty.I come from Sydney.I'm a student.I eat breakfast at home.And then I go to school at 8:30.Classes start at 9:00.After school,I usually play sports with my friends.On the weekend,I often take a dancing class and play music.Sometimes I watch TV and read books.
My favourite season is summer.Because Christmas is in summer.In Australia,summer is from December to February the next year.I usually go to the beach and swim on Christmas Day.What about you?
在往稀盐酸中逐渐滴入氢氧化钠溶液的过程中,当溶液的pH 达到2 时,溶液中的溶质有____