How do you say

This dress became small after a month of wear.

..in Chinese?

这件衣服穿了一个月就小了。

zhè jiàn yī fú chuān le yí gè yuè jiù xiǎo le 。

How do you say "I’ll sign up for the school’s English corner after the semester starts, and I aim to improve my spoken English in three months." in Chinese?