________about her son’s future, the mother has been sleeping very badly these months.
| A．Concerning | B．Concerned | C．To concern | D．Having concerned |
We should keep it in mind that beneath our feet ______ that our life depends on for food and clothing.
| A．lies the earth | B．lying the earth | C．does the earth lie | D．the earth is lying |
Crow considers the TV shows “a beautiful model of_______ I call high-tech learning. They can teach children about things in ways traditional education can’t.”
| A．which | B．why | C．what | D．that |
Over one thousand passengers remained_____ on trains for hours without air conditioning because of power failure on the railway,
| A．sticking | B．to be stuck | C．stuck | D．having stuck |
In order to help the police, the eyewitness described what he had seen very carefully not to______ any key clues.
| A．cut off | B．leave off | C．squeeze out | D．leave out |
Diaoyu Island issue, unless ________ properly, will directly affect smooth development of relationships between China and Japan.
| A．handling | B．having handled | C．handle | D．handled |