I use the following sentence construction a lot.
I'm not sure if this is right.
I was not aware of any problem until recently I noticed that quite a few of my colleagues used it a little differently. It went like:
I'm not sure this is right.
Now I'm confused. On the one hand, they are native speakers and might be correct on the usage. On the other hand, my education background convinces me that mine is correct too.
Which one should I use?