一直这个英文短语可以表达不同的意思，具体用法取决于上下文。以下是一些常见的用法：

1. "all along"：表示某事一直以来都在发生或存在。例如：

- I suspected he was lying all along.

- She knew the answer all along.

2. "all the while"：与"all along"类似，表示某事一直以来都在发生或存在，但更强调时间的延续性。例如：

- He was planning his revenge all the while she was talking.

- I was unaware that my phone had been hacked all the while I was using it.

3. "all day long"：表示整个一天都在做某事。例如：

- I've been cleaning the house all day long.

- We played basketball outside all day long.

4. "all the time"：表示一直在某个状态或做某件事情。例如：

- She's on her phone all the time.

- He's been sick all the time since we got here.

5. "always"：表示一直以来都是这样，通常用于描述人的性格或行为。例如：

- She always puts others before herself.

- He's always late for meetings.

总之，"一直"这个英文短语可以用于表达时间、状态、行为等方面的内容。需要根据具体场景选择合适的用法。