Direction: Arrange these parts so as to form a complete meaningful…

Correct sentence: Pollution needs to be tackled seriously; otherwise our future generations would suffer a lot.

• Place 'to be tackled seriously' immediately after 'Pollution needs' to complete the verb phrase 'Pollution needs to be tackled seriously.'

• Use 'otherwise' to introduce the consequence; 'otherwise' cannot directly follow 'Pollution needs' because it depends on the preceding clause.

• Follow 'otherwise' with 'our future generations would suffer a lot' so that 'our future generations' is the subject of 'would suffer a lot' and the consequence is clear.

Therefore, the correct arrangement of the parts is: 'to be tackled seriously' → 'otherwise our future generations' → 'would suffer a lot', which produces the sentence shown above.