What are clauses that cannot stand alone and complete thoughts called?

Clauses that cannot stand alone and complete thoughts are called dependent clauses or subordinate clauses.

Here's why:

* Dependent: They rely on an independent clause to make sense.

* Subordinate: They are "subordinate" to the main idea conveyed by the independent clause.

Example:

* "Because it was raining" (dependent clause) - This doesn't make sense on its own. It needs something like: "Because it was raining, we stayed inside."

* "When the bell rings" (dependent clause) - Again, this needs a main clause: "When the bell rings, we will go to lunch."

Let me know if you have any other questions!