Provided ThatHow to use the expression "provided that" correctly
The expression provided that is a subordinating conjunction (a conjunction that begins a dependent clause) meaning “if; only if; on the condition that”:
Each student will receive a stipend every month, provided that he or she attends class regularly and maintains good grades.
Provided that you work hard, you should succeed.
Common Errors in English Usage: Errors in diction and idiom commonly made by native speakers of English
List of Common Errors in English Usage (PDF): Printable version of the complete list
Common Grammar Errors: A list of common errors in grammar (topics like subject-verb agreement and parallelism) as distinct from usage