A.leg to stand
B.foot to stand
C.leg to lean
D.foot to lean

A.Out of job.
B.Out of hand.
C.Out of order.
D.Out of mind.

A.in hand
B.on hand
C.into hand
D.under hand

A.state
B.status
C.being
D.welfare

A.authority
B.right
C.way 
D.chance

A.protection
B.duty
C.responsibility
D.charge

A.reflect
B.bear
C.give
D.possess

A.reasons
B.excuses
C.grounds
D.foundation

A.come
B.reached
C.drawn
D.arrive

A.CaCO3 \(\xrightarrow{{{t^0}}}\) CaO + CO2.
B.CaSO3 + 2H+ ⟶ Ca2+ + SO2 ↑ + H2O.
C.CaCO3 + 2H+ ⟶ Ca2+ + CO2 ↑ + H2O.
D.CaCO3 + CO2 + H2O ⟶ Ca2+ + 2HCO3-