A.Sorry, but I didn’t mean to hurt you.
B.She’s acing all the tests!
C.Yes, she looks so lovely.
D.Thank you for that.

A.We are just looking.
B.Mind your own business.
C.We will order later.
D.Take care of yourself.

A.OK. No problem.
B.The same to you.
C.Yes, that's a good idea.
D.Thank you.

A.Yes, I'd like to.
B.OK. What's the matter?
C.That's great. Congratulations.
D.Well, you are right.

A.4HF + SiO2 ⟶ Si + 2H2O + 2F2.
B.3HF + Na2SiO3 ⟶ 2NaF + SiF + 3H2O.
C.4HF + SiO2 ⟶ SiF4 + 2H2O.
D.4HF + Na2SiO3 ⟶ 2NaOH + SiF4 + H2O.

A.4HF + SiO2 ⟶ Si + 2H2O + 2F2.
B.3HF + Na2SiO3 ⟶ 2NaF + SiF + 3H2O.
C.4HF + SiO2 ⟶ SiF4 + 2H2O.
D.4HF + Na2SiO3 ⟶ 2NaOH + SiF4 + H2O.

A.96%.
B.78%.
C.84%.
D.91%.

A.26,61.
B.25,96.
C.23,18.
D.29,57.

A.
B.
C.
D.

A.
B.
C.
D.