buy,bought,bought
lend,lent,lent
be,was（were）,been
go,went,gone
fly,flew,flown
sit,sat,sat
teach,taught,taught
read,read,read
understand,understood,understand
think,thought,thought
make,made,made
get,got,gotten
spend,spent,spent
write,wrote,written
ring,rang,rung
come,came,come
have,had,had
pay,paid,paid
sell,sold,sold,
bring,brought,brought
leave,left,left
sweep,swept,swept
see,saw,seen
take,took,taken还有send啊send，sent，sent