Thank you so much, susan. I didn't know about that thing with "enough". Maybe the reason I sounded unnatural compared with natives was my putting indefinite articles in wrong places. That could be explanation enough.
Actually, I've come across another sentence where "a" appears to be left out.
"Unlike in the UK where students from around the world are all mixed in together,
there is strict separation of domestic and international students’ dorms in China."
Shouldn't there be an "a" before "separation"? Or is "separation" here considered to be some sort of an abstract noun?
Additionally:
The sentence no.2 I quoted earlier now in full:
"It isn’t, of course, that Chinese people are inherently unkind. I could easily cite countless examples of altruism which have directly affected me during my stay in China (
a student coming round to my apartment with bottle of medicine she had bought for my cough; an eight-year old girl giving away her umbrella to me in the rain)."
Thanks