The research is so designed that once __________ nothing can be done to change it.
The old couple married for 40 years and never once____ with each other.
—How was the 2008 Beijing Olympic opening ceremony? —________ that the whole world was attracted.
海南三亚一中月考3,24)So difficult _______it to work out the problem that I decided to ask Tom for some advice.
Seldomas lonely as now though I have been living in Fuzhou for more than 20 years.
Only when their children leave home _________.