30天学会英语短语怎么说

"Learn Engpsh phrases in 30 days" is a way to say it. Here are a few other options:

"Master Engpsh phrases in 30 days"
"Become proficient in Engpsh phrases in 30 days"
"Acquire a strong foundation in Engpsh phrases in 30 days"
"Develop fluency in Engpsh phrases in 30 days"