49. ___
A. By eroding layers of sediment above it.
By traveling through cracks in layers of rock.
C. By reversing its flow down the aquicludes.
D. By boiling up through pores in the aquifer.
50. ___
A. It pushes the water upward.
B. It keeps the water cool.
C. It holds the water underground.
D. It creates holes in the aquiclude.
40. ___
A. The skills cowboys learned on the range.
B. The evolution of rodeos.
C. The recent decline in the popularity of rodeos.
D. The growth of the cattle industry.
41. ___
A. They were small informal events.
B. Competitors were awarded large prizes.
C. Large audiences attended them.
D. There were standard rules for judging events.
42. ___
A. It is the only traveling rodeo.
B. it is the largest agricultural fair.
C. It is the oldest annual rodeo.
D. It was the first rodeo to charge admission.
微信支付 
支付宝支付