"总是" means always and "永远" means forever. They can be both used as adverbs of degree, for example: "他总是忘记随手关灯" - "He always forgets to turn off the lights conveniently. "有些人可能永远保持单身" - "Some people may stay single forever. "永远" has a higher degree than "总是". And, "永远" can be also used as a noun: "我希望能陪伴你直到永远" - "I wish to keep your company till forever."

总是:para siempre- <el pasado，ahora，el futuro > 永远:de aquí en adelante-- hasta siempre

thank you

always and forever

總是 Is Always, in the sense of "oh, he always does that" "you're always late" 永遠 is forever, always in the sense"I will always love her" "we'll always be this way"