有关溶液中所含离子的检验,下列判断正确的是
A.加入硝酸酸化,再滴加KSCN溶液后有红色物质生成,则原溶液中一定有Fe3+存在 |
B.加入盐酸有能使澄清石灰水变浑浊的气体生成,则原溶液中一定有大量的CO32-存在 |
C.用某溶液做焰色反应实验时火焰为黄色,则该溶液中一定有钠元素,可能有钾元素 |
D.分别含有Mg2+、Fe3+、Al3+、Cu2+、Fe2+和Na+的六种盐溶液,只用NaOH溶液是不能一次鉴别开的 |
Charles was alone at home, with_______ looking after him.
A.someone | B.anyone | C.not one | D.no one |
It is often ______ that human beings are naturally equipped to speak.
A.said | B.to say | C.saying | D.being said |
I can’t leave. She told me that I ______ stay here until she comes back.
A.can | B.must | C.will | D.may |
—— Do you mind my opening the window? It’s a bit hot in here. —— ______ , as a matter of fact
A.Go ahead | B.Yes, my pleasure![]() |
C.Yes, I do | D.Come on |
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 |