下列关于磁感线的说法不正确的是（  ）

    It is Saturday morning. The sky is blue. My father and I are going to the park. There are a lot of people in the park. Some children are running on the grass. A dog is running after them. Some men are sitting on the grass. They are talking. Two girls are flying a nice kite. Three women are standing under a tree, and they are watching the children playing. There is a boat in the lake and two women are boating. Everyone in the park is very happy.

19世纪后30年，西方某国钢铁企业的数量减少了近140个，而工人总数却增加了近两万人，产量增加了近3000万吨，投资额增长了近五倍。这主要说明当时该国钢铁企业（   ）