如图，△ABC是边长为6cm的等边三角形，点D从B点出发沿B→A方向在线段BA上以a cm/s速度运动，与此同时，点E从线段BC的某个端点出发，以b cm/s速度在线段BC上运动，当D到达A点后，D、E运动停止，运动时间为t（秒）

Maria          wear a dress at the party yesterday.    

    I had worked that day, as a nurse. Now I faced the dirty supper dishes. I wanted to 1why Jimmy hadn't phoned as usual to say “Good night”to Bob and Tom. “Maybe Daddy's 2 working on an accident,” I said to Bob. “Go to3 now. You'll see him in the morning.”Soon there was a knock at the door. “There4 be something wrong with your phone,” my neighbor told me. “The City Police Station wants you to 5.”
    I went into the living room and dialed. Then I 6 the words every police wife fears (害怕): “Your husband has been hurt.” When I reached the hospital, my heart sank (下沉). The entrance was jammed with TV-news trucks. In the 7  I saw Jimmy’s best friend, Smith. “Just tell me -is he alive ?” I asked.
    Smith 8. and didn't answer. Then I found my younger sister, Mandy. “He’9s ”she told me, and we began to cry together.
Later, Smith told me 10 had happened.
    In the morning, when my little Bob asked, “Where's Daddy?” I 11  him into my arms and tried to explain. “A bad man 12 Daddy last night.” I said. “Daddy can't come home any more. He's in heaven(天堂) now.”
My son looked at me, his blue eyes 13 the picture of trust(相信). “Do they have14 in heaven ?”he asked. “Can I call him ?”
“No, Bob, Daddy still loves you, but Daddy can't15”.

阅读文章，回答问题。

     今黄生贫类予，其借书亦类予；惟予之公书与张氏之吝书若不相类。然则予固不幸而遇张乎，生固幸而遇予乎？知幸与不幸，则其读书也必专，而其归书也必速。

     为一说，使与书俱。

课文结尾“为一说，使与书俱”表达了作者的____情感。

汽车的启动电源常用铅蓄电池，放电时的电池反应如下：PbO₂ + Pb + 2H₂SO₄ = 2PbSO₄+ 2H₂O，根据此反应判断下列叙述中正确的是（   ）