音标：/tr/
对应的字母组合：tr

11'

tree

6'

truck

7'

train

8'

音标：/dr/
对应的字母组合：dr

7'

draw

8'

dress

9'

drink

10'

driver

11'

音标：/ts/
对应的字母组合：ts

6'

cats

7'

boats

8'

skirts

8'

coats

7'

音标：/dz/
对应的字母组合:ds

22'

birds

9'

beds

7'

friends

12'

87'