The company reformatted the invoices so that overseas clients ____ read the totals at a glance. The options are read, could, so, and enough. Learners who see so that and expect a plain statement pick read. The intended answer is could — a purpose clause after so that needs a modal, not a bare present verb. This guide sorts out when so that marks a purpose and takes a modal, and when the surface-similar so ... that marks a result and does not.
Purpose versus result: one connector, two jobs
The trap in this family is that so that and so ... that look almost identical but do opposite work:
- Purpose —
so that+ modal.We labeled every box **so that** the movers **could** find them fast.(The labeling was done in order to achieve an outcome. The clause states a goal.) - Result —
so ... that+ statement.The boxes were **so** heavy **that** the movers needed a cart.(The heaviness caused a consequence. The clause states what actually happened.)
The tell is the word between so and that. If an adjective or adverb sits there (so heavy that, so quickly that), you are in result territory, and the clause is a plain statement — the same construction covered in result clause so, such, too, enough selection. If so and that sit next to each other (so that), you are in purpose territory, and the clause needs a modal.
Which modal belongs in a purpose clause
Purpose clauses do not take a bare present verb. They take one of a small set of modals, and the choice tracks the tense of the main clause:
- Present or future main clause →
canorwill.We keep a backup server **so that** the site **can** stay online during updates. - Past main clause →
couldorwould.We kept a backup server **so that** the site **could** stay online during updates. may/mightappear in more formal registers:The policy was revised **so that** staff **might** report concerns anonymously.
In the opening item, the main clause is past (reformatted), so the purpose clause takes the past-side modal could. read is the trap — a bare verb that ignores the purpose-clause rule; so and enough do not fit the slot at all.
In order that: the formal sibling
In order that is the more formal equivalent of so that, and it follows the same modal rule:
The figures were footnoted **in order that** auditors **might** trace each entry.
TOEIC favors so that in most items, but in order that shows up in formal reading passages and occasionally as a Part 5 answer choice. When you see it, expect the same modal (can/could/will/would/may/might) — never a bare present verb.
Do not confuse it with the infinitive of purpose
English has a shorter way to state purpose: the infinitive to or in order to. The difference is whether the two clauses share a subject:
- Same subject → infinitive.
The team stayed late **to finish** the report.(The team stays; the team finishes.) - Different subject →
so that+ modal.The team stayed late **so that the client could** see a draft by morning.(The team stays; the client sees.)
Part 5 exploits this by giving a sentence with two different subjects and offering an infinitive as a distractor. If the doer of the purpose is not the doer of the main action, the infinitive is wrong and so that + modal is right. This subject-tracking discipline is the same one that governs subjunctive mood after verbs of demand and suggestion, where the base-form verb in the that-clause also refuses a bare present tense.
The comma tell
A quick punctuation check separates purpose from result in ambiguous items:
so that(purpose) is usually not preceded by a comma:Send the file early so that we can review it.- A comma before
sooften signalssoas a coordinating conjunction meaning therefore:The file arrived early, so we reviewed it.
That second so is neither purpose nor result — it simply joins two independent clauses. If a comma sits before so and no that follows, treat it as and therefore, and expect a full independent clause after it.
Decision checklist for the exam
- Is there an adjective or adverb between
soandthat? → result clause, plain statement, no modal. - Do
so thatsit together (or is itin order that)? → purpose clause, needs a modal. - Present/future main clause →
can/will; past main clause →could/would; formal →may/might. - Same subject in both clauses? → an infinitive (
to/in order to) may be the intended shorter answer instead. - Comma before a lone
sowith nothat? →someans therefore; expect a full clause.
Work these five checks in order and the purpose-clause items in Part 5 stop being guesswork. The modal is never optional inside so that — spotting the missing modal is usually the fastest route to the answer. For a broader view of how degree and result distractors are built, review reading inference scope and degree distractor elimination.