Tom ___ downloaded a virus into his computer, hecan not open the file now．

Having completed our adventurous journey through the forest, we went back to our camping site, ____.[ ]

Many students are not __________ the harm of staying up late into the night, which causes damage to their health.

I wondered what difficulty he had ______ the plan?[ ]

_______ the children grew old, they became more and more _______ in science.