知道了為什么現(xiàn)在塑料袋是可降解的了,因為不是從石油里制造出來的,是植物里提取的。
Wide range of cross-curricular
topics in graded English Attractivephotos, charts and diagrams helpunderstanding In every book:
activities and projects for languageand learning skills Flexible designallows both free reading and
supported reading Picture
Dictionary (levels 3 and 4) and
Glossary (levels 5 and 6) offer extrasupport Audio in both American
and British English Excellent
teacher materials Fiction partner