I'm not entirely sure what is suppose to follow 是否. For example, I'd like to say:
I wasn't know (or wasn't sure) if you heard me clearly.
I'm not sure if this is how it should be translated:
我没确定你是否听清楚出我刚说的话
I'm also curious if this is correct:
我没确定你是否听到了我。
How should the above be properly translated? And, more importantly, how do I use 是否 in general?