A.speak
B.teach
C.meat
D.ear

A.common
B.come
C.brother
D.none

A.kidding
B.signal
C.whistle
D.slight

A.maximum
B.jump
C.summarize
D.abrupt

A.clap
B.catch
C.wave
D.handle

A.clap
B.catch
C.wave
D.handle

A.\(S = \left\{ {\left( {1, - 1} \right);\left( {3,0} \right)} \right\}.\)
B.\(S = \left\{ {\left( {0, - 1} \right);\left( {3,0} \right)} \right\}.\)
C.\(S = \left\{ {\left( {0, - 2} \right);\left( {3,0} \right)} \right\}.\)
D.\(S = \left\{ {\left( {0, - 3} \right);\left( {3,0} \right)} \right\}.\)

A.3.
B.4.
C.2.
D.1

A.Na2CO3.
B.NaHCO3.
C.NaHSO4.
D.Na2SO4.

A.AgNO3/NH3.
B.Cu(OH)2.
C.Br2.
D.(CH3CO)2O.