①加适量盐酸; ②加过量Na2CO3溶液; ③过滤;
④加过量NaOH溶液; ⑤加过量BaCl2溶液.
I'm making progress this term, so I am very proud ________ myself.
-2-(-6)÷(-3)=( )
—Let's buy tomorrow.
如图所示,一束光线斜射入容器中,在P处形成一光斑,在向容器里逐渐加水,直到加满的过程中,光斑将( )