We know the fact______the energy makes the cells able to do their work.A．thatB．whichC．what

The survival of civilization as we know it is ____

The second paragraph focuses on the fact that ______.A．fossil energy was once very cheapB．

The main function of the hormone is to control the bodys biological clock, ______ we know

Jason failed one of the exams, but we should make_____for the fact that he had been ill fo

According to the news item, we know that the stain is actually representing the______.A．wo

From the first paragraph we know that __________.