I can ______ be a teacher. I’m not a very patient person.
43. Learning a foreign language well takes a long time, ________?
42. Many countries are increasing their use of natural gas, wind and other forms of ________.
41. —Well, it's getting late. I must be going. Thank you again for inviting me to the party. —________
40. —Shall Tom go and play football? —Not ________ he has finished his homework.
39. Was ________ Bill, ________ played basketball very well, ________ helped you repair your bike?