检查给定的句子是否符合英语语法规则，并指出错误所在。
"We was going to the store but then we seen that it was closed."
The given sentence does not follow English grammar rules. The correct sentence would be: "We were going to the store but then we saw that it was closed." The correct forms of the verbs "be" and "see" are "were" and "saw," respectively.