Provided the input sentence, you're expected to write a question that involves event "frequency", which refers to how often an event is likely to be repeated. For example, "taking showers" typically occurs ~5 times a week, "going to Saturday market" usually happens every few weeks/months, etc. Don't create questions which have explicit mentions of answers in the text. Instead, it has to be implied from what is given. In other words, we want you to use "instinct" or "common sense". Also, the written questions are not required to have a single correct answer.
Q: Sentence: Sarawak's coast and jungle interior were controlled by the Iban — Sea Dayak pirates and Land Dayak slash-and-burn farmers.
A: 
How often had the Iban had control of the Sarawak's coast?