这位老农大概有三四个孩子，而且他们现在都长大成人，可以在地里干活了。

[误] The old farmer has about three or four children, who have now grown up and are able to work in the

fields.

[正] The old farmer has three or four children, who have now grown up and are able to work in the fields.

注：汉语可以说“大约有三四个孩子”，但翻译成英语却不行。因为about 后面不能接约数，而应该接确定的数目。即：要么去掉 about，只用 three or four;要么用 about，但后面接 three 等具体的数字。