“毛毛虫”与“蝴蝶”分别是昆虫发育的哪个时期（ ）
---How do you like the scarf?
---Very much. It _________ soft.
物质
氢气
原煤
（主要成份是C）
汽油
（主要成份C8H18）
热量（kJ）
285.8
250.9
4910
—What do you often do _______ classes to relax yourselves?
— We often chat together, do eye exercises or do some running around the school.
— Thank you for inviting me.
