这几句话对不对?I have joined the organization in the last few years

这几句话对不对?
I have joined the organization in the last few years.
The city has became more and more beautiful in the last few years.
除了第二句“became”因改为become，还有什么错吗？

　　第一句可改为：I have been in the organization in the past/last few years.
　　第二句中：became-->become,其它没问题.
再问： in the last few years 是表示时间段的状语的状语么？
再答： 　　是的，“在过去的几年里”，也常说“in the past few years”。
再问： 如果是这样的话，The city has become more and more beautiful in the last few years.应该是错的，因为become是瞬间动词，不能与表示时间段的状语连用
再答： 　　瞬间动词不能与表示时间段的短语连用主要是指下面的时间短语：for+时间段，since+时间点，别把这个说法的应用范围扩大，草木皆兵。再者，本句中“变得越来越美”是一个过程，也不是瞬间完成的，这个become相当于been，实际是系动词的用法，也不是纯粹的实义动词里的瞬间动词。