写出下列动词的四种形式

例：do does doing did done

forget ________ ________ ________ ________

写出下列动词的四种形式

例：do does doing did done

spell ________ ________ ________ ________

写出下列动词的过去式形式。

写出下列动词的四种形式

例：do does doing did done

write ________ ________ ________ ________

写出下列动词的四种形式

例：do does doing did done

understand ________ ________ ________ ________