无船承运人并不实际拥有船舶，但是可以签发实际承运人的海运提单。

（1）瓦斯中甲烷与氧气的体积比为1：2时极易发生爆炸，此时甲烷与氧气的质量比为______．

（2）现有0.284kg质量分数为10%的Na₂SO₄溶液，则溶液中Na₂SO₄的物质的量为______．

（3）配制250mL2.0mol/LH₂SO₄溶液，需要18mol/LH₂SO₄溶液的体积______mL．

第四部分：写作（共三节，满分45分）

第一节：单词拼写（共10小题，满分10分）

请根据每句所给单词的汉语以及句子结构将英语单词写在每题右边的横线上。

51. Professor Li is very __(热心) about his teaching.                                                  51._________

52. Her teaching is not like that of my __(以前) teacher.                                                     52._________

53. The __(表现) of the students in class shows they like her.                                               53._________

54. The ­­__(少年) felt unhappy because their team failed.                                                     54._________

55. Your listening __(理解) needs improving.                                                                    55._________

56. They looked at the car until it __(消失) in the darkness.                                                 56._________

57. History is not an __(学术) subject.                                                                   57._________

58. Secondary school in the US usually __(包含) seven years.                                         58.__________

59. His __(厌倦) speech made us sleepy.                                                                        59.__________

60. He always __(鼓励) us when we failed.                                                                    60.__________

急性胰腺炎增强扫描的主要目的是（）

A.判断有无胰腺坏死灶及其范围，推断病变的程度

B.观察胰腺与十二指肠的关系

C.观察胰腺与肾前筋膜的关系

D.观察胰腺与结肠肝曲及脾曲的关系

E.观察胰腺与脾静脉的关系

固体氢氧化钠露置于空气中，质量会增加，原因是：

（1）______

（2）______．

车辆在上坡翻倒之前，可能因轮胎与道路附着力不够而（）

A、发生倒溜

B、发生倒滑

C、无关