Can someone please tell me if these two sentences are subordinating conjunctions, I think they are:

Additionally, I remember a time when the sports world was honest, and drug-free. the 2nd one is: And I bet I can still hit it across that fence in your back yard. Thanks

Sentences are not subordinating conjunctions.

However, one of them contains a subordinating conjunction. Check this site.

http://englishplus.com/grammar/00000377.htm

Thanks. So I can start my sentences with although, when, and as long as, and it would be right, right? Thanks again

Yes, you can begin sentences with coordinating conjunctions.

However, in formal writing, sentences should not begin with "And."

To determine if these sentences contain subordinating conjunctions, we need to identify any words that join independent and dependent clauses.

The first sentence: "Additionally, I remember a time when the sports world was honest, and drug-free."

In this sentence, the word "Additionally" is not a subordinating conjunction. It is an adverb that functions to add information. It does not introduce a dependent clause.

The second sentence: "And I bet I can still hit it across that fence in your backyard."

In this sentence, the word "And" is not a subordinating conjunction either. It is a coordinating conjunction that joins two independent clauses.

So, neither of the sentences contains subordinating conjunctions based on the examples you provided.