题目

One day，a man telephoned Norman Vincent Peale．He was in great depression （沮丧，意气消沉）and told Morman that he had nothing left to live for．Peale invited the man to his office．“Everything is gone，and I'm hopeless，”the mall told him．”I'm living in the deepest darkness．In fact，I've lost heart for living altogether．’’     Norman Vincent Peale smiled sympathetically（同情地）．”Let’s take a look at your situation，”he said calmly．On a piece of paper he drew a straight line down the middle．He suggested that they list on the left side th19世纪，世界上很多著名的科学家试图通过研碎胰腺的方法来提取其中的胰岛素，但都没有获得成功；后来有科学家采用先通过结扎胰管让胰腺退化，然后单独研碎胰岛的方法成功提取了其中的胰岛素。下列关于失败原因的分析中，最可能的是 A．当时研磨技术比较落后，研磨不充分 B．研磨时选取的胰腺部分正好不含有胰岛 C．研磨过程中，胰腺中的消化酶把胰岛素分解了 D．胰岛素和胰腺内的其他物质紧密结合，不容易分离