Problem-solution essays first pair every cause with an executable solution.

Common mistake

A slogan-like solution, or one unrelated to the earlier cause, cannot form a complete response even when solution language appears.

• Whether every cause has a matching solution
• Whether the actor and action are explicit
• Whether the mechanism leads to the expected effect

The hard requirement: causes and solutions must pair up

The most common structural failure in problem/solution essays: the problem paragraph names causes A and B, but the solution paragraph prescribes medicine for C. Say the problem paragraph attributes congestion to "cheap private car use" and "scattered urban planning", and the solution paragraph offers "governments should promote environmental awareness" — the campaign answers neither cause. In scoring terms this is a broken TR development chain: a solution's persuasiveness depends entirely on whether it answers the causes you yourself named. Draw a cause-to-solution mapping line before writing — one to one, and delete any solution without a partner.

Worked example: a mechanism-free vs a mechanism-backed solution

Mechanism-free: "The government should take measures to solve traffic congestion. For example, they can improve public transport. This will make the situation better." Three sentences, none explaining how it gets better. Mechanism-backed: "Since congestion here stems from car commuting being cheaper than the bus, the fix must invert that price gap: congestion charging in the city centre, with the revenue funding higher bus frequency. When driving costs more and the bus arrives every five minutes, a share of commuters switches — and each switched car frees road space for those who still must drive." Every step answers who, through what, changing which behaviour.

Why the government-cures-all pattern loses marks

Writing every solution as "the government should" is this type's highest-frequency double weakness in LR and TR: the single subject narrows lexical range, and more importantly, the real actor for many problems is not the state — consumer habits, employer scheduling, and school curricula each hold their own lever. Two distinct actors in the solution paragraph (state pricing plus employer staggered hours, say) lift argument credibility and lexical variety in one move.

• Tag each solution's actor: state, business, individual, school
• At least one solution with a non-government actor
• End each solution with one expected-effect sentence

Two minutes before writing: the cause-solution matrix

Two columns on scratch paper: the two most important causes on the left; on the right, one solution per cause with an actor and a mechanism, then draw the lines. Any solution that cannot connect stays out of the essay. These two minutes preempt both of this type's big deductions — broken pairing and the cure-all — far more cheaply than post-hoc checking.