When you go outing with your sisters, you must see to ________ that they are safe.
14. --- It’s thirty years since we last met. --- But I still remember the story, believe it or not, ______ we got lost on a rainy night.
13. ___ had they reached the 30th floor ____ they realized that they had forgotten to take the key.
12. Bungee is an adventurous sport, popular with young adults, ______ courage matters more than strength.
11. The public has complained that large quantities of waste water ______ into rivers without being cleaned, so large amounts of money ______ to solve the problem.
10. The World Wide Web is sometimes jokingly called the World Wide Wait because it ______ be very slow.