用更相减损术求38与23的最大公约数为____

河蚌身体柔软、体外有外套膜、包被有贝壳，属于（   ）

短文改错

    During the summer holidays, I thought I should do anything meaningful instead of touring. So I got a job at fast food restaurant and worked there for a cleaner. I worked 7 hours a day for three week. The job was hard and boring and seemed endless, it made me so tired that I nearly left it halfway. Therefore, I stuck to it with determination. Every day I start off for work early in the morning and got to home late in the evening. Finally, I finished the job before the new school term began. Now, I understand that labor means. I consider it a successful experience, which is worth remembered forever.

下列材料出自近现代某政治文件，这个政治文件最有可能是（    ）