51.   If ice is available at the site of the lunar base, then the situation is dramatically different.

52.   If you are a person at greater risk from flu, consider having a flu vaccine this autumn.

53.   In general, children stay in the same percentile band they were in at birth.

54.   In the lowest-lying places, which are flooded at any slight rise in the water level, no trees grow.

55.   Barney was quiet at first, but gradually he became more confident.?

56.   They offered her the job, initially on a temporary basis but later as a full member of the staff.

57.   It can be tricky at first, but persevere.

58.   It might be thrilling at first, but it will probably end in pain and tears.

59.   Many activities are available at the hotel at no extra cost, but theatre trips and excursions are not included.

60.   Not much is said, as each young person, and Bill, is hard at work at the task at hand.