问题
问答题 简答题
在不改变目镜和目镜测微尺，而改用不同放大倍数的物镜来测定同一菌体大小时，其测定结果是否相同？为什么？
答案
参考答案：
相同。因为同一菌体的大小是一定的，不同放大倍数的物镜不会改变菌体的实际大小，但物镜的放大倍数越高，目镜测微尺的精确度越高，测量月准确。
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在不改变目镜和目镜测微尺，而改用不同放大倍数的物镜来测定同一菌体大小时，其测定结果是否相同？为什么？
参考答案：
相同。因为同一菌体的大小是一定的，不同放大倍数的物镜不会改变菌体的实际大小，但物镜的放大倍数越高，目镜测微尺的精确度越高，测量月准确。
| 阅读理解。 | ||
| Ever since we became pen pals, Julien has sent me strange things. Once, she sent her sneeze in a jar. ("I have a cold, can you tell?" she wrote. ) Then she sent her fingerprint. ( "So you'll recognize me in a crowd.") Julien sent me breakfast, all right: cornflakes. Soggy, milky, grainy, crumbly, limp cornflakes scraped from the bottom of her cereal bowl. I lost my appetite, but I read the letter.
"I don't know," Mom said."Julien might find a way. After all, she did send you her sneeze. A week later I checked the mail and found a box with air holes and the words "FRAGILE-THIS SIDE UP" printed in bold black letters on the top. It was from Julien. I stroked the box with my fingers. It was perfectly dry. I smelled it. It didn't smell. I held my breath and started opening the package. What if sunbeams spring out and hit me in the face like those fake snakes in a can; I thought? My hands shook as I lifted the last flap and peeked inside. Where in the world was the sunset? All I could find was a letter and a twisty, gray, papery shell. It looked like a submarine. I read the letter.
Julien," I said. Without reading the postscript, I laid the letter and the submarine on the kitchen table. Then I left the room to find a pen so that I could cross out "sun-set" and write "submarine" above it. When I returned, I stared in shock at the submarine. A creature was oozing out of it! Was it a sea monster? I looked closer. It was a winged creature... an insect... a butterfly. An orange, blue, purple, red, and gold butterfly. It looked like... a sunset! While the sunset opened and closed its wings to dry them, I read Julien's postscript. It said, "P. S. Next week I'm sending you Japan." | ||
| 1. What does the underlined word "oozing" probably mean? | ||
| A. moving B. jumping C. swimming D. flying | ||
| 2. What did Julien really want Caitlin to see in the fourth mail? | ||
| A. The setting sun. B. Colors of a sunset. C. A colorful butterfly. D. A new submarine. | ||
| 3. We can learn from the passage that Julien was ______. | ||
| A. strange and clever B. honest and friendly C. creative and giving D. funny and inventive | ||
| 4. What can be inferred from the passage? | ||
| A. Caitlin was from Japan and had never seen Julien. B. Caitlin's mom thought Julien's gifts were fantastic. C. Caitlin was pleased with the cornflakes that Julien sent. D. Caitlin was expecting another unusual gift from Julien. |