将给定的一段英文文本中的各种时态改变，并在输出中显示修改后的文本。
As a software engineer, John worked on several projects during his career.
Present Simple: 
As a software engineer, John works on several projects during his career.

Present Continuous: 
As a software engineer, John is working on several projects during his career.

Present Perfect:
As a software engineer, John has worked on several projects during his career.

Past Simple:
As a software engineer, John worked on several projects during his career.

Past Continuous:
As a software engineer, John was working on several projects during his career.

Past Perfect:
As a software engineer, John had worked on several projects during his career.

Future Simple:
As a software engineer, John will work on several projects during his career.

Future Continuous:
As a software engineer, John will be working on several projects during his career.

Future Perfect:
As a software engineer, John will have worked on several projects during his career.