proportion of leaf to stem

例句：

1. 1. The proportion of the population that isoverweight is increasing.
   超重人口比例在增加。
2. 2. The ratio of male to female studentsin the class is about equal.
   班上男生和女生的比例大致相等。
3. 3. The scientistfound a new ratio forthe reaction, which could beuseful for further experiments.
   科学家发现了反应的新比例，这可能对进一步的实验有用。