写出下列动词的过去式。 1. am /is_______ 2. are _______ 3. see_______ 4. write _______ 5. stand _______ 6. hear ________ 7. give _______ 8. catch_______ 9. feel _______ 10. grow _______ 11. eat _______ 12. go _______ 13. have / has _______ 14. teach _______ 15. come_______