总是 VS 一直

Both words are used to indicate that a certain action won't change. "总是" is used to emphasize that the action never changes, regardless of time. And "一直" is used to emphasize that an action will not change at present. For examples:

• 雨总是下个不停。
• 雨一直下个不停。

Both of these sentences mean "to rain without stopping". The first sentence implies that "It always rains in this area". The second sentence implies that "It has been raining all day long".

“总的来说”常用做插入语，表示从总体上或从主要情况来评论。
"总的来说" is usually used as a parenthesis, meaning "on the whole, generally speaking".