So suddenly_______that the animals in the zoo looked very frightened during the total solar eclipse.
| A．did the sky turn dark | B．the sky did turn dark |
| C．turned the sky dark | D．was the sky turned dark |
He was encouraged to start again _________ he had failed.
| A．where | B．in which | C．when | D．what |
By this time next year we from the college.
| A．will be graduating | B．should be graduating |
| C．will have graduated | D．is graduating |
_______, people injured in the earthquake are _______.
| A．Generally; picking up | B．Sadly; picking up |
| C．Luckily; setting up | D．Fortunately; picking up |
Some scientists think there are _______ 2，000 million flashes of lightning per year.
| A．in short | B．on average | C．as usual | D．in total |
Whenever we are in ______ trouble, we should never lose______ heart.
| A．a; the | B．a; a | C．/; / | D．/; the |