完形填空,阅读下列短文，掌握其大意，然后从1—20各题所给的A、B、C、D四个选项中，选出最佳选项。
Hot lava flows down a Hawaiian mountainside. Farther up the slope, volcanologist（火山学家）Ken Hon picks his way slowly across the____surface. The hot lava（岩浆）is slippery to walk on. “It’s like walking on ice,” Hon says. “But the bottom part of your boots starts to____ a little. You’ll get burned____you fall.”
Hon plants his feet carefully and slowly. He’s____ data on the lava flowing out of Kilauea, a volcano that has been erupting since 1983. ____the lava’s movements can save lives on the slopes below. But Hon must be____. New waves of lava are flowing down toward him. Every few minutes he looks up to see ____the streams are and makes sure the____lava hasn’t cut off his escape route.
“It’s___out there, like the heat from an oven,” Hon says. “Up close, you have to wear firefighters’ clothes____the clothes you’re wearing don’t catch fire or melt.”
“Back in 1990, lava entered the town of Kalapana. The lava moved slowly but steadily,” Hon says. “We____ evacuate(疏散) people from about 150 homes. The lava____forward and consumed all of the houses.” ____, everyone escaped. But today Kalapana is buried under 30 feet of lava.
Volcanoes aren’t____to Hon. They’re fascinating and exciting. “My____thing is to come out at the edge of a lava lake. Sometimes I’ve had to sleep with a gas mask on.” Still, Hon knows how to keep____ and knows when the lava is ____. “All of a sudden, it gets really bright inside your____!” he says, laughing. But the____is worth it, because the more Hon and other scientists can____volcanoes, the safer they can keep the people who live around these powerful forces of nature.

A．calm B．frozen C．flat D．rough

A．bend B．sink C．melt D．fly

A．though B．because C．if D．unless

A．collecting B．providing C．exchanging D．sharing

A．Knowing B．Stopping C．Filming D．Remembering

A．smart B．careful C．silent D．creative

A．where B．how C．which D．what

A．hardening B．moving C．cooling D．amazing

A．powerful B．crowded C．empty D．hot

A．or B．while C．but D．so

A．had to B．ought to C．should D．could

A．leaned B．inched C．put D．looked

A．Strangely B．Fortunately C．Hopefully D．Gradually

A．similar B．interesting C．scary D．important

A．lucky B．main C．worrying D．favorite

A．safe B．busy C．comfortable D．quiet

A．different B．distant C．close D．slow

A．bag B．tent C．car D．house

A．change B．view C．result D．danger

A．think of B．talk about C．learn about D．hear of