We take 'lessons on' ethics, morality, etc, but we take 'lessons in' subjects. As forgiveness is not a subject but an attribute, hence, option (1) is the correct answer.

Whenever we refer to a period or duration of time we use preposition 'for'. Usage of auxilary 'have' (present tense case) eliminates the chances for the usage of option 3 and 4, as both of them are the cases of past tense. Hence, option 2.

Case of article usage. Though the word 'European' starts with a vowel but it does not make a vowel sound. Hence, article 'a' is the correct choice.

“To be convinced of” is an idiom which means “to be of the confirmed view'' which is conveyed in the given sentence. Hence, (1) is the correct answer.

Case of present perfect tense. Hence, (3) is the correct answer. Present perfect tense shows that something started in the past and continues in the present.

“To wipe out” is an idiom which means “to clear away” which is conveyed in the given sentence. Hence, (1) is the correct answer.

In a compound sentence dealing with a coordinate clause, both the clauses should be in the same tense. Hence, (4) is the correct answer.

“To consist in” is an idiom which means “to be filled with”/"lies within" which is conveyed in the given sentence. Hence, (3) is the correct answer. 

“To come along” is an idiom which means “to accompany with” which is best conveyed in the given sentence. Hence, (1) is the correct answer.

The given sentence refers to the present perfect continuous tense indicating a period of time. Hence, (4) is the correct answer.

“To keep under” is an idiom which means “to keep under surveillance” which is conveyed in the given sentence. Hence, (3) is the correct answer.

“To hanker after” is an idiom which means “to run after” or “to pursue madly” which is best conveyed in the given sentence. Hence, (1) is the correct answer.

”To solve” is the only option which has an infinitive. Moreover, adjective 'too' is always followed by infinitive 'to'. Hence, (2) is the correct answer.

“To go through” is an idiom which means “to read” which is conveyed in the given sentence. Hence, (1) is the correct answer.

”To be fast at” is an idiom which means “to be quick at “which is conveyed in the given sentence. Moreover, we are 'good in' subjects, but 'fast at' practices (like calculations). Hence, (3) is the correct answer.

”To blow out” is an idiom which means “to extinguish” which is conveyed the given sentence. Hence, (4) is the correct answer.

The given sentence is of coordinate clause which must have both the clauses in the same tense. The tense is past perfect continuous. Hence, (4) is the correct answer.

“To cordon off” means “to surround” which is conveyed by the given sentence. Hence, (2) is the correct answer.

“To see through” is an idiom which means “to understand or to be able to understand” which is conveyed by the given sentence. Hence, (2) is the correct

It is clear in the sentence that when the uncle entered the room, the letter writing activity was also under the process. To show this parallel continuity of two actions of the past, we use past continuous tense. Hence, (1) is the correct answer.

The given sentence refers to the present perfect continuous tense showing the point of time. Hence, (4) is the correct answer.

The given sentence belongs to the Adverb clause of time and it being a complex sentence must have the same tense. Hence, (4) is the correct answer.

“To put in order” is an idiom which means “to set in order” which is conveyed by the given sentence. Hence, (3) is the correct answer.

Providing break through” is an idiom which means “to provide a forcible passage through a barrier” which is conveyed in the given sentence. Hence, (4) is the correct answer.

It is an adverb of comparative degree which shows a comparison between the uses of penicillin and sulphanilamide. Hence, (2) is the correct answer.