用赤霞珠酿造的优质葡萄酒有很好的陈年潜力是因为( ) A: 高单宁低酸High tannins and low acidity B: 低单宁高酸Low tannins and high acidity C: 低单宁低酸Low tannins and low acidity D: 高单宁高酸High tannins and high acidity

Rieslings are usually __________ wines with high natural acidity and distinctive _________ attributes. The presence of toasty, kerosene notes indicates __________.

According to______ level, canned foods include low-acid foods, medium acidity foods, and high- acid foods.

Which of the following aids in the absorption of calcium? A: Caffeine B: Low stomach acidity C: Iron D: Vitamin D

萃取过度的espresso, 主要表现出的风味是什么?What is the taste of overextracted espresso? A: 酸acidity B: 甜sweetness C: 苦bitterness

萃取不足的espresso,主要表现出的风味是什么?What is the taste of underextracted espresso? A: 酸acidity B: 甜sweetness C: 苦bitterness

If the pH value of foods is in the range of 3.7 to 4.5, we can call this kind of foods as food. A: medium acidity B: low-acid foods C: high- acid foods D: None of the above

(1) The weak monoprotic acid HA is 2.5% dissociated in 0.10 mol·L-1solution. What is the acidity constant, Ka, of HA?(2)A certain solution of HA has a pH=2.51. What is the concentration of the solution?

这个单词 ‘brut’在香槟酒标上是指...( ) A: 桃红酒Rose in colour B: 高单宁High in tannin C: 低酸Low in acidity D: 干Dry

Which of the following is part of a positive feedback mechanism associated with global climate change? A: increase in the gas mileage of cars B: increase in the cloudiness caused by more moisture in the atmosphere C: melting of Arctic sea ice D: increase in the acidity of seawater E: increase in the growth of CO2 absorbing trees and grasses