索赔性质属于( )。A．补偿性 B．制裁性 C．教育性 D．惩罚性

如图所示，光从空气斜射向玻璃砖，请画光出在玻璃砖中的折射光线（保留作图痕迹）

One Monday morning, Paul and his classmates were in science laboratory for their practical chemistry lesson. The students were going to work in pairs to do an experiment. Before they began, the teacher gave them this description of the different stages of the experiment.

Stage 1: Prepare the equipment: a test tube, a crucible, a Bunsen burner and tongs.

Stage 2: Weigh 5 grams of baking soda (sodium bicarbonate) and put it in a crucible.

Stage 3: Heat 10 ml of hydrochloric acid (盐酸) in a test tube.

Stage 4: Pour the warm acid onto the baking soda and continue to heat the mixture.

Result: The acid reacts with the bicarbonate（碳酸氢盐）to form water, carbon dioxide gas and salt. The hotter the mixture, the quicker the reaction. Continue to heat the mixture until the water evaporates, leaving the salt in the crucible.

Paul and his partner followed the instructions and set up their equipment. Paul went to the cupboard to get a bottle of hydrochloric acid. He found that there was only one bottle in the cupboard so he took that. There was no label on the bottle and Paul didn’t check with the teacher if it was the right solution.

He measured the liquid and poured it into a test tube. Using tongs to hold the test tube, he heated it over the Bunsen burner. That’s when things started to go wrong. The liquid in the test tube was not hydrochloric acid. When it was heated, it formed a thick cloud of white gas. Soon the room was full of this strong smelling white gas.

All the students started coughing and their eyes hurt. The teacher immediately opened the windows and ordered the students to leave the laboratory at once. She realized that the liquid was a crylamide (丙烯酰胺) and that it is poisonous.

Fortunately, nobody was injured in the incident. However, it taught the students and the teacher a good lesson.

小题1:What lesson did the incident teach the students and the teacher?

A．Never have a bottle without a label in the chemistry lab!

B．Obey your teacher’s instructions in the Chemistry lab.

C．A crylamide can’t take the place of hydrochloric acid.

D．Finding something unusual happened, you have to leave the laboratory at once.小题2:What substance were the students making in the experiment?

A．Water

B．Carbon dioxide gas

C．Salt

D．Poisonous gas小题3:Why did Paul make the mistake?

A．He went to the cupboard to get the bottle by himself.

B．He found that there was only one bottle in the cupboard so he took that.

C．There was no label on the bottle.

D．Paul didn’t check with the teacher that it was the right solution.小题4:Why did the teacher send the students out of the classroom?

A．Becausethe room was full of this strong smelling white gas.

B．Because all the students started coughing and their eyes hurt.

C．Becausethe liquid was a crylamide and that it is poisonous.

D．Because someone was injured in the incident.

Sentences can be ________ into clauses, and clauses into phrases.

A．broken in

B．broken through

C．broken up

D．broken away

“蹦极”是一富有刺激性的运动项目。某人身系弹性绳自高空P点自由下落，如图所示。a点是弹性绳的原长位置，c点是人所到达的最低点，b点是人静止地悬吊着时的平衡位置。不计空气阻力，则下列说法中正确的是

A、从点a至点b的过程中，加速度方向与速度方向相反

B、从点P至点c的过程中，重力所做功等于人克服弹力所做的功

C、从点a至点c的过程中，加速度方向保持不变

D、从点P至点b的过程中，人的动能不断增大

患者6个月前，上前牙小洞在外院复合树脂充填后一直有冷热痛。近1周疼痛加重，不敢咬合。查：右上中切牙近中舌侧充填体完好，叩诊（++），扪痛（+），牙髓无活力。该患者牙的诊断是（）

A.急性牙髓炎

B.牙髓坏死

C.慢性牙髓炎

D.急性根尖炎

E.可复性牙髓炎