Expressing "all along" with 一直 (yīzhí) is pretty easy. Character for character, it literally means "one straight," and it's sort of like saying "constantly."

Basic Structure
This structure expresses the continuation of an action or a circumstance.

Examples:

Wǒ yìzhí zài xiànzài de ɡōnɡsī ɡōnɡzuò.
我 一直 在 现在 的 公司 工作。
I've always worked at this company.

Cónɡ zhèlǐ yìzhí zǒu, shí wǔ fēnzhōnɡ hòu nǐ huì kàn dào yī ɡè dà ɡōnɡyuán.
从 这里 一直 走，十 五 分钟 后 你 会 看 到 一 个 大 公园。
If you keep walking from here, 15 minutes later you will see a big park.

 

Structure
一直 can also be used to indicate a range or scope, such as time or place. It is often used in the 从…一直（+V.）+到… grammar structure.

Examples:

Cónɡ zǎoshɑnɡ liù diǎn yì zhí dào wǎnshɑnɡ shí èr diǎn, tā dōu zài ɡōnɡzuò.
从 早上 六点 一直 到 晚上 十二点，他 都 在 工作。
From 6 o'clock in the morning all the way until 12 o'clock at night, he is constantly at work.