per mu yield的用法和樣例：
例句
- Due to the bad weather,cotton yield poer mu is very low this year.
由於天氣不好，今年棉花的畝產量很低。 - The yield is over 1,000 jin per mu.
畝產過千斤。 - A farmer told me once that it was a big problem to explain how some small farms were getting higher yields per acre than the big farms.
有一次一位農民告訴我，要解釋一些小農場畝產比大農場要高真是個大問題。
