The diference between DO and DE please...
Eu gosto DO chá. I like of tea (an specific tea). Eu gosto DE chá. I like tea (every type of tea)
Do = de + o (literally "of/from the") for masculine words. De = of/from
Woudn't it be gosto?
No. You have to conjugate verbs accordingly: http://www.conjuga-me.net/verbo-gostar