The scientist __________ the experiment for half a year, but he _______ yet.
The research also raises the question ________ children from low-income, less educated families need earlier aid.
Most volunteers are from universities, _________ it is not uncommon to see middle and primary school students too.
Since her only child passed away a few years ago, family has been a ________ topic for her.
Outdoor activities are as much a part of childhood for this generation of Chinese children as they __________ for their parents and grandparents.
An important feature of consumer society is that we gain self-confidence through ______ we own.