Communicating Clearly

I beg your pardon/ Pardon, but can you say that again?

Sorry, I can't  catch your meaning, can you repeat that?

Excuse me, what do you mean by that？/ what does this mean?

I'm so sorry, I can't understand your meaning, could you clarify it for me?

Sorry, I lost you, what did you say?

Sorry, I don't understand you clearly, could you be more specific?

Sorry, I didn't follow, could you repeat that? 

I'm not following you, could you repeat that? 

Glossary

abbreviation [əˌbriːviˈeɪʃn] 缩略词，缩写形式；缩略，缩写

aesthetic [esˈθetɪk] adj. 审美的，美学的；美的，艺术的 n. 美感，审美观；美学（aesthetics）；美术理论

benevolent [bəˈnevələnt] adj. 仁慈的，乐善好施的；（用于慈善机构名称）慈善的，救济的

fastidious [fæˈstɪdiəs] adj. 挑剔的；苛求的，难取悦的；（微生物等）需要复杂营养地