单项选择题 The incredible precision of the equipment is ______ to the mechanical skill of the engineers who built it.

问答题 Listen to the following passage. Altogether the passage will be read to you four times. During the first reading, which will be read at normal speed, listen and try to understand the meaning. For the second and third readings, the passage will be read sentence by sentence, or phrase by phrase, with intervals of 15 seconds. The last reading will be read at normal speed again and during this time you should check your work. You will then be given 2 minutes to check through your work once more. Please write the whole passage on ANSWER SHEET ONE.

单项选择题 This type of apparatus can produce more than 40,000 blood ______ a day.