46.I’m sorry to ()your party; I weren’t in town.

49.A country ( )birth rate is higher than its death rate will have an increasing population.

48.()his last word，he got into a taxi and disappeared in time.

47.The best way to make friends is to start a conversation with someone and ()what your common interests are and go from there.

46.Very few people understood his lecture， the subject of ()was hard.

45.After being tested in many ways， this newly-designed machine will ()in the near future.

44.Most people prefer ()money to ()it.

43.Public attention at the moment is ()the problem of industrial relations.

42.He swallows his words so much that I can never ()what he is saying.

41.Important people don’t often have much free time as their work ()all their time.

40.Theory is based on practice and ()serves practice.