影响混凝土搅拌最短时间的因素有()。

The argument in the passage leads most naturally to which of the following conclusions？

A．A low output of urinary kallikrein is a likely cause of high blood pressure in children.

B．The kallikrein-kinin system plays an important role in the regulation of blood pressure.

C．Essential hypertension may have biochemical precursors which may be useful predictors in children.

D．The failure of the body to produce sufficient amounts of kinins is the cause of essential hypertension.

The argument in the passage leads most naturally to which of the following conclusions？

A．A low output of urinary kallikrein is a likely cause of high blood pressure in children.

B．The kallikrein-kinin system plays an important role in the regulation of blood pressure.

C．Essential hypertension may have biochemical precursors which may be useful predictors in children.

D．The failure of the body to produce sufficient amounts of kinins is the cause of essential hypertension.

A. Extreme temperature variances

B. Extreme humidity variances

C. Power stability fluctuations

D. Excessive dust accumulation

Which of the following group of people is most likely to be interested in the talk？

A．Tourists.

B．Mountaineers.

C．Poachers.

D．Businessmen.

The passage would most likely be found in a textbook on which of the following subjects？

A．Astronomy.

B．Botany.

C．Geology.

D．Chemistry.

The passage would most likely be found in a textbook on which of the following subjects？

A．Astronomy.

B．Botany.

C．Geology.

D．Chemistry.

Which of the following is most likely to be bugged？

A．International telephone calls.

B．International printed messages.

C．Domestic printed messages.

D．Electric typewriters.

Which of the following is most likely to be bugged？

A．International telephone calls.

B．International printed messages.

C．Domestic printed messages.

D．Electric typewriters.

The passage would most likely be found in a texbook on which of the following subjects？

A．Astronomy.

B．Botany(植物学).

C．Geology.

D．Chemistry.