What if anything, is wrong with the following sentence?
The new drug proved to be highly effective, it has no side effect.
a. Comma splice
b. Properly constructed sentence.
c. Lacks parallel parts
d. Has unclear pronoun
This is an example of a comma splice.
You have two complete sentences which should be separated by a period or a semicolon. You can rewrite this sentence in two or more ways.
The new drug proved to be highly effective; it has no side effects.
The new drug proved to be highly effective. It has no side effects.
The new drug proved to be highly effective, and it does not have side effects.
I think the last sentence is the most effective.
http://grammar.ccc.commnet.edu/grammar/runons.htm
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