某溶液A，可能含有等物質(zhì)的量濃度的SiO₃^2-、CO₃^2-、SO₃^2-、S^2-、AlO₂^-、Cl^-、PO₄^3-中的幾種，現(xiàn)進(jìn)行以下實(shí)驗(yàn)：

（1）以10mLA溶液，往其中通入足量的CO₂，得到白色沉淀B，B可完全溶于稀硫酸。

（2）另取10mLA溶液，往其中加入稀硫酸，生成氣體C，將C通入Pb(NO₃)₂溶液中，有黑色沉淀D生成。

問(wèn)題：

（1）溶液A中肯定存在：_____________________________________.

（2）溶液A中肯定不存在：______________________________，其理由是：___________________.

根據(jù)“三氟化硼→正三角形→非極性分子”的因果關(guān)系，則“三氯甲烷→（ ① ）→（ ② ）”的因果關(guān)系是

      A、正四面體       B、非正四面體     C、非極性分子     D、極性分子      E、四邊形

答案：①_____________;②__________________.

氯化碘(ICl)的化學(xué)性質(zhì)跟氯氣相似，預(yù)計(jì)它跟水反應(yīng)的最初生成物是……( )

A、HI和HClO     B、HCl和HIO     C、HClO₃和HIO     D、HClO和HIO

某地有甲、乙兩工廠排放污水，污水中各含有下列8種離子中的4種（兩廠不含相同離子）：Ag⁺、Ba²⁺、Fe³⁺、Na⁺、Cl^-、CO₃^2-、NO₃^-、OH^-。若兩廠單獨(dú)排放都會(huì)造成嚴(yán)重的水污染，如將兩廠的污水按一定比例混合，沉淀后污水便變成無(wú)色澄清只含硝酸鈉而排放，污染程度會(huì)大大降低。關(guān)于污染源的分析，你認(rèn)為正確的是（ ）

     A、CO₃^2-和NO₃^-可能來(lái)自同一工廠              B、Na⁺和NO₃^-來(lái)自同一工廠

     C、Ag⁺和Na⁺可能來(lái)自同一工廠               D、Cl^-和NO₃^-一定不在同一工廠

Progress______ so far very good and we are sure that the work will be finished on time.

A. was       B. had been    C. has been    D. will be

It’s high time you had your hair cut ; it’s getting _______ .

A. too much long       B. much too long

C. long too much       D. too long much

They use computers to keep the traffic _______ smoothly. 

A. being run       B. run         C. to run        D. running

I’m sure that your letter will get______ attention. They know you’re waiting for the reply.

 A. continued   B. immediate   C. careful   D. general

It’s high time you had your hair cut ; it’s getting _______ .

A. too much long       B. much too long

C. long too much       D. too long much

Jenny nearly missed the flight______ doing too much shopping. 

A. as a result of      B. on top of    C. in front of      D. in need of