问题
选择题
将物体放在离凸透镜30cm处，恰好能在光屏上得到一个等大的清晰的像；当物体放在离凸透镜20cm，并移动光屏，在光屏上成[ ]
A．倒立的缩小实像
B．倒立的放大实像
C．正立的放大虚像
D．无像
答案
答案：B
搜题请搜索小程序“爱下问搜题”
将物体放在离凸透镜30cm处，恰好能在光屏上得到一个等大的清晰的像；当物体放在离凸透镜20cm，并移动光屏，在光屏上成[ ]
A．倒立的缩小实像
B．倒立的放大实像
C．正立的放大虚像
D．无像
答案：B
完形填空（共10小题；每小题1分，满分10分） Having a few days off always sounds so great. Everyone needs a 1 . And so does US President.US President Barack Obama went on holiday with his family in 2 in 2011. Where did they go and did the first family enjoy 3 ? Now, Obama is trying to 4 his experience (经历) with us. Let’s listen to him. “We travelled to Honolulu, Hawaii, in December 2011 for 5 . Of course we went there by air. We spent 17 days there. Hawaii is my hometown. We had a wonderful time there. This was one of the 6 vacations in my life. My wife Michelle and I visited US Marines (海军) and their families in Hawaii on Christmas Day. I 7 held the eight-month-old baby of a captain in my arms. I also spent part of Christmas Eve playing golf with my old friends from Hawaii and some White House staff. I went to Hanauma Bay Nature Park with my 8 daughters. That’s our favourite place. We dived there, 9 set four sea turtles free. We all had a good time. And both my daughters said that they wanted to go there for a 10 time later.”
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