On August 14, 1996, a tiny drop     1     a very toxic（有毒的）chemical called dimethyl-mercury（二甲基汞）fell onto the left hand-of Karen Wetterhahn, a toxicologist and professor of chemistry at Dartmouth College. Wetterhahn was an expert on     2     toxic metals cause cancer. When the poisonous drop fell onto her hand, she wasn’t     3     (worry); she was wearing protective gloves.

    4     (unfortunate) the dimethyl-mercury went through her glove. After a while, Wetterhahn     5     (have) difficulty walking and speaking. After three weeks, she was in a state of deep unconsciousness. Karen Wetterhahn died five months later. She was 48 years old, a wife and mother of two.

You might say that a toxicologist studies substances that lead to     6     (die). But toxicology is also about saving lives. What can kill, can cure. Medical     7     (research) such as Weterhahn risk their lives daily for the benefit of others. Their work is dangerous, but it has the potential     8     (save) lives. In memory of Wetterhahn’s life and work, Dartmouth College created the Karen Wetterhahn Memorial Award. The award     9     (give) to female science students     10     receive money to continue their scientific research.

Sammy   Armstrong   was   driving   to   his office   when   he     1    (notice)   a car was stuck on railroad tracks. Then he heard a train whistle. Sammy threw down his sunglasses and keys and ran toward the car.    2    elderly man, Jean Papich, eighty­four, sat in the driver’s seat,    3     (turn) the key and hitting the gas. His wife, Marion, seventy­eight, was looking     4    (nervous) at him. Then Sammy walked    5    the car and pushed it forward, but his boots slipped on the warm asphalt (沥青).He could see the train approaching fast.

It might be    6    (easy)to push the car backward, Sammy thought. He ran around to the front to the vehicle and shouted at Jean     7    (put)the car in neutral(空挡). Sammy could feel the ground trembling under his feet. He put his boots against the track and pushed forcefully. Finally, the car rolled off the tracks. When Sammy looked up, the train was just a couple of     8    (foot )away. Sammy, shocked and     9    (speech), went back to work as the crowd gathered at the scene.

Weeks later, Marion called to thank Sammy. He responded, “I just did     10    I had to do.”