Use methods that permit direct investigation of the question. 使用直接調查研究問題的研究方法。
These direct investigations aim at addressing problems at a higher level by adopting a proactive and preventive approach. 進行直接調查的目的，在於以積極主動的態度，從較高層次著手解決問題。
Most information was collected by direct observation of the animals' behaviour. 大部份信息都是通過直接觀察動物的行為收集到的。
Ophthalmoscopy affords the only opportunity for direct visualization of blood vessels. 檢眼鏡檢查法提供直接觀察血管的唯一機會。
