—You'd better _______ the workers into two groups and ask them to take turns to work.

19＋{#blank#}1{#/blank#}=27

8＋19={#blank#}2{#/blank#}

50＋6={#blank#}3{#/blank#}

{#blank#}4{#/blank#}＋50=56

20＋34={#blank#}5{#/blank#}

34＋{#blank#}6{#/blank#}=54

如图所示，半径为R的光滑圆环竖直放置，直径MN为竖直方向，环上套有两个小球A和B，A、B之间用一长为 $\sqrt{3}$ R的轻杆相连，小球可以沿环自由滑动，开始时杆处于水平状态，已知A的质量为m，B球的质量为4m，重力加速度为g．

如图所示，半径为R的光滑圆环竖直放置，直径MN为竖直方向，环上套有两个小球A和B，A、B之间用一长为 $\sqrt{3}$ R的轻杆相连，小球可以沿环自由滑动，开始时杆处于水平状态，已知A的质量为m，B球的质量为4m，重力加速度为g．

35＋4={#blank#}1{#/blank#}

81＋9={#blank#}2{#/blank#}

35＋4={#blank#}1{#/blank#}

81＋9={#blank#}2{#/blank#}

—Don't be shy. Believe in yourself and everything will be OK.

—Don't be shy. Believe in yourself and everything will be OK.

—Don't be shy. Believe in yourself and everything will be OK.

    Michael had taught us English for two years before he moved to New York. He worked very hard and was patient with his students, so we all 1 him very much since he left. It was not long before Michael came back to Los Angeles 2 a short visit. The teachers and students held a small party for 3.

    At the party, people walked 4 and talked with each other. I certainly would not give up the good 5 to learn English. I tried to think of all kinds of topics 6 with another English teacher, Mrs. Green.

    Just before I was going to run out of my 7, suddenly I heard Michael say to others loudly, “I dig New York!” I asked Mrs. Green at once, “Is it really 8 to find a job in New York? Why does Michael have to do 9 work since he is such a good teacher?”

    Mrs. Green didn't seem to understand 10 I said. “Why do you think of that?” she asked.

    “Haven't you heard him say that he is digging New York? Is he 11 an underground passage(地下通道)?” I asked.

    When Mrs. Green finally 12 what I meant, she laughed to tears. Then she asked us whether we knew the 13 of “I dig New York”. All of us shook heads and said “14“. Michael told us that “I dig New York” means “I love New York” in American slang(俚语). 15 few people say that now, we still hear it sometimes.

如图若将某植株一片叶的主脉切断（图中甲），另一片叶两面都贴上不透明的锡箔纸（图中乙），黑暗中放置24小时后再光照4小时．取下两叶经脱色后用碘液处理，发现A部位呈棕褐色，B部位呈蓝黑色，C部位不呈蓝黑色．以上实验能够证明光合作用需要（  ）