_____ from the top of the tower, the south foot of the mountain is a sea of trees.

Storm chasing is so dangerous that some chasers are often hurt in accidents ______ by driving in a heavy rain.

In April, thousands of holidaymakers remained ________ abroad due to the volcanic ash cloud.

Some English scientists are identifying problems ____ technology in the 21st century. If solved, the solutions could change the world.                         

 When it comes to____his classmates with the homework, he never feels tired.