English Language

The word 'sifting' correctly fits the sentence as it means to examine carefully and separate what is useful from what is not, which matches the context of going through accumulated junk. The other options are either incorrect words or do not fit the context.

The correct indirect speech for 'He says, I shall be here' is 'He says that he will be there' because the first-person pronoun 'I' changes to 'he', 'shall' changes to 'will' in reported speech, and 'here' changes to 'there'.

Option A correctly uses 'cause and effect' to describe the relationship that remains the focus of scientific investigation, with proper singular agreement. Option B incorrectly uses 'affect' instead of 'effect'. Option C incorrectly pluralizes 'relationships' which changes the meaning. Option D is incorrect as option A is correct.

The word 'divulge' means to reveal or disclose information, which fits the context of not revealing further information to avoid jeopardizing the investigation. The other options do not fit as precisely in this context.

The correct preposition to use with 'benefitted a great deal' in this context is 'from,' as it indicates the source or cause of the benefit. Therefore, 'Benefitted a great deal from taking that online training course' is correct.

The sentence is a negative statement, so the tag question must be positive. "Do you" is the correct positive tag to match the negative statement. The other options do not fit grammatically or logically.

Option A correctly transforms the active sentence 'We must write to him' into the passive voice as 'He must be written to.' This maintains the modal verb 'must' and the preposition 'to' at the end, which is appropriate in English passive constructions with indirect objects.

The word 'offend' means to cause displeasure or hurt feelings. The opposite would be to praise or express approval, which is best captured by 'acclaim'. The other options do not represent opposites of 'offend'.