。
Was she able to write the report?
Literal
[topic-は] report [object-を] write [nominalizer-こと-が] could [question-か]?
~ことができる is the formal/written potential construction — 'is able to do X.' It's roughly synonymous with the bare potential form (書ける), but slightly more formal and often preferred in writing. こと nominalizes the verb phrase, and できる ('to be able') takes that nominal as its subject (marked with が). The polite past ~ました shifts to ~ましたか for a question. レポート is a loanword that in school/university contexts means a written assignment or paper — distinct from English 'report' (in business contexts, レポート can also mean a presentation or formal report).