阅读理解

　　If you're training for a marathon, a proper plan for water intake(摄入)is important．Of course, there's the risk of dehydration(脱水)．But athletes now know they can also get into trouble by drinking too much．Too much water intake can lower levels of sodium(钠)in the blood．The death of a 28-year-old woman following the Boston Marathon caught the attention of many runners and led to new research．

　　Experts advise long distance runners to replace the liquids they sweat out．Their goal is to try to keep someone from not getting dehydrated by more than 2 percent of their body weight．

　　One technique for deciding how much water you need is to get the exact numbers．Runners have to weight themselves before and after a run to determine how much water they've lost．If their weight drops by more than 2 percent, they have not drunk enough water．

　　Hyponatremia occurs when runners drink so much water that blood salt levels drop off．A study published last year tested 488 runners who completed the Boston Marathon and found 13 percent of them had dangerously low blood salt levels．The first sign that runners may notice is slightly swelling in the hands．They can't get their rings off, and then they might feel sick．They may not remember where they are．In fact, most runners get enough salt to get back to normal levels by eating just one meal after a run．Contrary to the old advice that runners should drink as much as they can to prevent dehydration, the new research has shown that the body is a remarkable machine that actually tells you via thirst when you need water．

阅读理解

　　If you’re training for a marathon, a proper plan for water intake(摄入)is important．Of course, there’s the risk of dehydration(脱水)．But athletes now know they can also get into trouble by drinking to much．To much water intake can lower levels of sodium(钠)in the blood．The death of a 28-year-old woman following the Boston Marathon caught the attention of many runners and led to new research．

　　Experts advise long distance runners to replace the liquids they sweat out．Their goal is to try to keep someone from not getting dehydrated by more than 2 percent of their body weight．

　　One technique for deciding how much water you need is to get the exact numbers．Runners have to weight themselves before and after a run to determine how much water they’ve lost．If their weight drops by more than 2 percent, they have not drunk enough water．

　　Hyponatremia occurs when runners drink so much water that blood salt levels drop off．A study published last year tested 488 runners who completed the Boston Marathon and found 13 percent of them had dangerously low blood salt levels．The first sign that runners may notice is slightly swelling in the hands．They can’t get their rings off, and then they might feel sick．They may not remember where they are．In fact, most runners get enough salt to get back to normal levels by eating just one meal after a run．Contrary to the old advice that runners should drink as much as they can to prevent dehydration, the new research has shown that the body is a remarkable machine that actually tells you via thirst when you need water．

阅读理解

　　Reader Janet Maynard has a lot of young bushes in her garden and is suffering from “watering can elbow”．So for Janet and anyone else who doesn't want to waste time, effort and water, here are my top tips for keeping plants refreshed in thirsty times．

　　Water in the evening if possible, rather than leaving it till you see things suffer．That way the roots can take up the water in cool soil overnight．

　　Violently jetting hoses(皮管)mess up the soil structure and may expose delicate roots．Use a rose(喷头)on a can．Aim low – don't waste water wetting leaves, even though they look pretty and "refreshed"．

　　The most valuable and easily damaged plants need the most attention, such as newly planted trees, bushes and climbers．Remove any water-keeping mulch(护根物)you may have put around the base, then water it thoroughly at least two gallons, slowly．Don't aim your can rose at the stem – which we all usually tend to do．Aim the water in a wide circle so that the whole of the area under the plant is watered．You could even make a channel in the soil right around the plant so that the water is held in place as it soaks(浸透)in．Replace the mulch．Repeat each week even in showery weather for the first summer．

　　How much water for pots? Fill up the gap between the top of the soil and the top of the pot．Let the water soak right in and then fill it again．Do this daily in hot weather for most summer potted plants．

　　Stand pots in saucers(垫盘)– it makes a big difference．But remember to check that the plants are not sitting in water for days on end when the weather turns wet．Roots will rot．

　　If the fertilizer in pots really dries out, the water may get straight out of the pot without being absorbed．Correct this by standing or floating the pot in a bucket of deep water until it sinks and no bubbles rise．

　　A push-button watering can makes for more efficient watering, and recycled water bottles upside down with a needle which has a hole on the end are useful, too, for pots．