The first one means that you tried to stop feeling nervous or you tried to swallow so much that you couldn't.
The second one means that you are getting more nervous, or anxious.
Hope this was helpful!!!^_^
Answer:
I hope in the future, though I have my doubts, he will me forthright with such matters.
Explanation:
There are two commas because they represent breaks in the sentence. These are needed because, the part of the sentence "though I have my doubts" is basically a side comment. So, you add commas to show that.
<em>Writers use genres because of the cognitive and social work they accomplish. Using the patterns of a genre accepted by readers for accomplishing their purposes allows them to establish a working relationship with readers. But familiarity with genres can also make life easier for writers.</em>
The correct version is there are many threats to dolphins' continued existence, and humans are just one.