Global warming is a big _______ for all and it’s important to raise awareness about climate change.

A person of high ideals is highly respected. What people value is not based on outside ________.

I can’t say which sofa looks better. It’s just a (an) _____ of personal preference.

At first ______, the bag seems made of real leather. But actually it is just an imitation.　 

 He is _______as a leader but he hasn’t ________in teaching.