一到二十的基数词：

one

two

three

four

five

six

seven

eight

nine

ten

eleven

twelve

thirteen

fourteen

fifteen

sixteen

seventeen

eighteen

nineteen

twenty

一到二十的序数词：

first

second

third

fourth

fifth

sixth

seventh

eighth

ninth

tenth

eleventh

twelfth

thirteenth

fourteenth

fifteenth

sixteenth

seventeenth

eighteenth

nineteenth

twentieth