When one is "airing dirty linen in public", the person is:

• discussing private affairs in public
• hanging out clothes in the open to dry
• standing up and fighting
• complaining
Correct Option: A  [ discussing private affairs in public ]

Remark: "airing dirty linen in public": discussing or arguing about unpleasant or private things in front of other people.

The man cannot be trusted in the post for he has an itching palm.

• habit of taking bribe
• has an infectious disease
• habit of flattery
• a quarreling habit
Correct Option: A  [ habit of taking bribe ]

Remark: Itching palm: A desire for money, greed, wanting a bribe.

To drink like a fish:

• To drink little
• To drink alone
• To drink in company of others
• To be a drunkard
Correct Option: D  [ To be a drunkard ]

Remark:

It was he who put a spoke in my wheel.

• tried to cause an accident
• helped in the execution of the plan
• thwarted the execution of the plan
• destroy the plan
Correct Option: C  [ thwarted the execution of the plan ]

Remark:

No one dare call in question his honesty.

• Honesty of purpose
• Test
• Flatter
• Challange
Correct Option: D  [ Challange ]

Remark:

He says he has invented a time machine, which is clearly a load of cobblers.

• Genuine
• Great
• Nonsense
• Significant
Correct Option: C  [ Nonsense ]

Remark: "A load of cobblers" is indeed an idiom, and it is commonly used to express that something is nonsense, untrue, or of poor quality.

For the first week, the apprentice felt like fish out of water.

• frustrated
• homeless
• disappointed
• uncomfortable
Correct Option: D  [ uncomfortable ]

Remark:

The policy has been declared to be null and void.

• Invalid
• Empty
• Valid
• Impossible
Correct Option: A  [ Invalid ]

Remark:

He is in deep water and needs your help.

• great difficulties
• under the water
• a sea
• pain
Correct Option: A  [ great difficulties ]

Remark: "deep water" meaning: in a difficult or awkward situation.

His oily tongue has won him promotion.

• soft speech
• word power
• flattery
• fluency in speech
Correct Option: C  [ flattery ]

Remark: