In 2003, figures showed that there were 840,000 HIV carriers and 80,000 AIDS patients in China, _____ it the worst-affected country in Asia next to India.
I failed in the final examination last term and only then __________ the importance of study.
Only when your identity has been checked __________.
The old couple have been married for 40 years and never once __________ with each other.
Only after my friend came __________.
I have been living in the United States for twenty years, but seldom __________ so lonely as now.