Do you remember who gets angry because you forget to tidy up your room before going out? Do you remember who feels 1 with your dress from head to feet? This person is2 your boss nor your friend. It's funny that you have to 3 to her even though you sometimes don't like to hear anything she has said. It’s our mother, a great 4 in the world to us.
       I always5 my mother if we have a “long time no see”. But this kind of missing is always quieted down by 6 because I come back home for comfort and 7 but mum always puts more pressure on me. Of course, I know she 8 about me too much and just has a lot of words to tell me. But the 9turns to be pressure. On the other hand, I hurt her and make her feel lonely even though I am 10 her. Then what can we do? This problem is really hard to deal with. I think not 11 I have this problem. Here are my ideas. When we find there are some unhappy things going to12, shall we just stop for 30 13? Give me a chance to rest in your arms and we sing a childish song together just like when I was 14? I need your love indeed but without telling me to do as you wish me to. And then let's go out for a walk hand in hand. Tell me what's in your 15 gently and slowly. I will feel better if you don't just pour them out.

生物体能够由小长大的主要原因是（  ）

某英语杂志社刊登广告，组织中学生利用暑假时间去美国进行为期两周的夏令营（summercamp）活动，假如你是中学生李华，想报名参加，请你根据以下要点写一封邮件。你想参加夏令营的原因；你的英语水平；咨询住宿（accommodation）条件及费用注意：1. 字数在100字左右；可适当增加细节，使行文连贯；开头语已给出，不计入总次数。

Dear Sir or Madam,

    I noticed your advertisement that you would organize a summer camp in America during the summer holiday.

Sincerely yours,

Li Hua

已知$\left|\overrightarrow{OA}\right|=\left|\overrightarrow{OB}\right|=1,\angle AOB=\frac{2\mathrm{\pi }}{3},\overrightarrow{OC}=\overrightarrow{OA}+2\overrightarrow{OB},$则$\left|\overrightarrow{OC}\right|$与$\left|\overrightarrow{OB}\right|$夹角为（  ）

⑴调节天平平衡时，调节天平平衡时，应将游码移至____处，若发现天平的指针偏向分度盘的右侧，应将平衡螺母向____调（填“左”或“右”），直至天平平衡．

⑵用天平测出石块的质量m₁．

⑶如图甲所示，将烧杯中装入适量的水，置于天平上，平衡时的读数为m₂．

⑷如图乙所示，接着用细线将石块拴住，使之完全浸没在上述烧杯的水中，天平平衡时的读数为m₃（此时手向上拉住细线另一端，石块不触杯壁和杯底，水不外溢）．

⑸若水的密度为ρ_水，石块的密度表达式为ρ_石=____．

⑹此实验过程中若将（3）（4）顺序对换，则所测密度的误差是偏____．