Involve, include and contain

The words 'involve', 'include', and 'contain' are often used in English and have similar but distinct meanings.

'Involve' often means to make or allow something to take part in something. It suggests that the subject is directly engaged or participating in the matter or activity being described. For example, "The project involves a lot of work" means that a lot of work is a necessary part of the project.

'Include' means to make or allow something to be part of something. It does not necessarily imply active participation, but can merely indicate the presence or addition of something. For example, "The price includes tax" means that the tax is part of the price.

'Contain' usually refers to something being inside of something else. For example, "The box contains toys" means that there are toys inside the box.

In summary, 'involve' often refers to active participation, 'include' refers to being part of something, and 'contain' refers to something being inside of something else.