Unit 3I can swim very fast
Let's chant:
read, read, read, read fast.jump, jump, jump, jump high.write, write, write, write well.swim, swim, swim, swim fast.sing, sing, sing, sing well.
Summary
can 作为情态动词，表示能力，后面须跟动词原形。我们可以用副词well, fast, high等修饰动词，表示动作完成的程度。be good at 表示擅长...，后接动名词或名词。