Here is the original item:
To stomach the cup of strong coffee that he desperately needed to keep awake.
Lawrence added seven packets of sugar and a quarter cup of cream.
You chose to use a comma to connect the infinitive phrase to the end of the main clause, like this:
Lawrence added seven packets of sugar and a quarter cup of
cream,
to stomach the cup of strong coffee that he desperately needed to
keep awake.
Unfortunately, you cannot connect these two parts in this manner. Review the rules.