 complex sentences with because and when. A complex sentence has three parts. An independent clause, this is a complete sentence by itself. For example, I feel stress. A dependent clause, this has a subject and a verb but it is not a complete sentence. It begins with a coordinating conjunction. It must go together with an independent clause. For example, because I am worried about money. A subordinating conjunction is a word that puts the two clauses together. For example, because or when. A complex sentence example, I feel stress when I am worried about money. Structure. The independent clause can be first. For example, I feel stress because my child is sick or the dependent clause can be first. Because my child is sick, I feel stress. Note, when the dependent clauses first use a comma. Here are some examples of sentences that are wrong. Because my child is sick, period, that is an incomplete sentence. Because my child is sick, I feel stress. That sentence is wrong because it has no comma. Use. Use because to give a reason. For example, I feel stress. Why? Because my child is sick. I feel stress because my child is sick. Use when to tell a time. I go for a walk. When? When I feel stress. I go for a walk when I feel stress. More examples. I sleep a lot because I have stress. Because I have stress, I sleep a lot. I eat a lot of sugar because I have stress. Because I have stress, I eat a lot of sugar. I go for a walk when I feel stress. When I feel stress, I go for a walk. I feel better when I talk to someone. When I talk to someone, I feel better.