Đang chuẩn bị liên kết để tải về tài liệu:
IELTS Writing Test Answers 1

Anyone who has visited a dentist has been told that eating excessive amounts of sweets risks harming the teeth. This is because sweets lower pH levels in the mouth to dangerous levels. When the pH level in the mouth is kept above 5.5 acidity is such that teeth are unlikely to be in danger of decay. | Answers Practice Writing Paper 1 Task 1 Anyone who has visited a dentist has been told that eating excessive amounts of sweets risks harming the teeth. This is because sweets lower pH levels in the mouth to dangerous levels. When the pH level in the mouth is kept above 5.5 acidity is such that teeth are unlikely to be in danger of decay. Sweet foods however cause pH in the mouth to drop for a time and the longer pH levels remain below 5.5 the greater the opportunity for decay to occur. By comparing fruit sugar cane sugar and honey which are all common ingredients of sweet foods we find that cane sugar lowers pH levels for the longest period thus producing the greatest risk of the three. Approximately five minutes after consuming cane sugar pH levels drop to as little as pH 3.5. They then begin to rise slowly but do not rise above pH 5.5 until at least 30 minutes have elapsed. By contrast fruit sugar which causes the mouth s acidity to fall to just above pH 4 poses a danger for a shorter period tooth decay is unlikely 20 minutes after consumption. Honey appears an even less risky substance. Though acidity falls to about pH 4.75 within five minutes of consumption it returns to above pH 5.5 in under fifteen minutes. The implications then are that people who insist on eating sweet foods should be aware of the ingredients and that fruit sugar or honey appear preferable to cane sugar. 242 words Task 2 Mandatory retirement age varies from society to society perhaps a reflection of economics population pressures or simply value systems. Indeed retirement at 50 can probably be as easily justified as that at 70. It is my belief however that the longer an able person is allowed to work the better for both the individual worker and the employer. Chronological age is not always a true indicator of ability. While some 65-year-olds may not perform as well as they did in their past many workers at this age do just as well or better than they used to. People s suitability for a .