The general impression of snorkelling the writer gives is that________.

Read the passage carefully and choose the correct answer.

           The excitement of snorkelling in a clear tropical sea is hard to explain to someone who hasn't done it. If you expect to have the opportunity of trying it when on holiday, it is well worth bringing a snorkel if you can get hold of one. Experts now recommend a separate breathing tube.

            Many swimmers take a deep breath before diving with a snorkel. This is a mistake, because it makes the body so light that you dive with difficulty. It is best to take a couple of deep breaths and then a normal relaxed breath in order to breathe in enough for dive. Don't take repeated deep breaths before diving because this can lead to shortage of oxygen, which causes unconsciousness without warning.

            The backs of many snorkellers get badly burnt, for the snorkellers are so involved in the world below they forget about the dangers of sunburn. The sea does not protect your back from the rays of the sun, and it is best to wear a T-shirt. Snorkellers should also consider wearing shoes (or slippers), which may protect their feet from cuts from sharp rocks which can easily become infected.

What does the writer find difficult about snorkelling?

Fill in each numbered blank with one suitable word or phrase.

Rowing is a sport in which athletes race against each other on river, lakes or on the ocean, (1) _____ on the type of race and the discipline. The boats are propelled by the reaction forces on the oar blades (2) _____ they are pushed against the water. The sport can be both recreational, focusing (3) _____ learning the techniques required, and competitive where overall fitness plays a large role. It is also one of (4) _____ oldest Olympic sports. In the United States, Australia and Canada, high school and collegial rowing is sometimes referred to as crew.

(5) _____ rowing, the athlete sits in the boat facing backwards, towards the stern, and uses the oars which are held in (6) _____ by the oarlocks to propel the boat forward, towards the bow. It is a demanding sport requiring strong core balance as well as physical (7) _____ and cardiovascular endurance.

Since the action of rowing (8) _____ fairly popular throughout the world, there are many different types of (9) _____. These include endurance races, time trials, stake racing, bumps racing, and the side-by-side format used in the Olympic Games. The many different formats are a result of the long (10) _____ of the sport, its development in. different regions of the world, and specific local requirements and restrictions.