Modal verbs

Modal verbs are auxiliary verbs that indicate modality, that is, likelihood, ability, permission, and obligation.

Examples

  • Can

  • Could

  • Must

  • May

  • Shall

  • Should

Can

  • Use can for recommended actions. Also consider using "recommend".

  • Use can to express that it is technically possible.

  • Use can to give permission.

Examples

  • Yes: You can also provide all the profile information. That makes it easier for others to find you.

  • Yes: We recommend that you fill in the profile information. That makes it easier for others to find you.

  • Yes: After providing valid credentials, you can use the full version of the software.

  • No: You should/may provide all the profile information.

Could

  • Use "could" when talking about a weak possibility, or something that might happen.

  • When talking about a possibility, use "can".

Examples

  • Yes: If the connection is slow, the download could stop.

  • No: You could also provide all the profile information. This could make it easier for others to find you.

Must

  • Use must to express a necessity, a logical conclusion, a prerequisite, or a technically required necessity.

  • Do not replace must with have to.

  • Do not use should instead of must.

You can also use the imperative form to express necessity. Example: Uninstall the program before installing the new version.
Examples

  • Yes: You must uninstall the program before installing the new version.

  • Yes: Uninstall the program before installing the new version.

  • No: You should uninstall the program before installing the new version.

  • No: You have to uninstall the program before installing the new version.

May, shall

  • Do not use may or shall.

Should

  • Do not use should to express an expected result. If you use should, the user might think that the software will not carry out the action reliably. Instead, use simple present to describe the outcome of an action or process.

  • Do not use should for recommended actions. Instead, use can.

Examples

  • Yes: Click Run to create the report. The software generates a result.txt file and saves the file in the Results folder.

  • No: Click Run to create the report. The software should generate a result.txt file, which can be found in the Results folder.