We have delicate constitution and throughout our life likely suffer from various illnesses. When you are ill, you must be unpleasant on account of your body 61 (usual) becoming hot, and there are pains all over your body. You may have no desire to work and just stay in bed, 62 (feel) very sad.
What 63 (make) us ill? It is germs(病菌). Germs, 64 can't be found with your naked eyes, are everywhere. They are very tiny 65 you can still see them with a microscope. There could be 66 (ten) of hundreds of them on a very small thing.
Germs are always in dirty water. When we look at dirty water under the microscope, we shall see them in it. So you won't be allowed 67 (drink) dirty water by your father and mother.
Germs exist in water and often they 68 (find) in air and dust as well. If you cut your finger, if some of 69 dust from the floor goes into the cut, some of the germs will go into your finger. Your finger will become big and red, and you will feel very 70 (pain). Sometimes the germs will enter into ail of your body, and you will have pain everywhere.
答案 61. usually 62. feeling 63. makes 64. which 65. but
66. tens 67. to drink 68. are found 69. the 70. painful