Tā yīgè rén zuò sān gè rén de gōngzuò, yālì zhī dà kěxiǎng'érzhī.
He does the work of three people - you can imagine the pressure.
Tips
grammar
可想而知 usually comes at the end of a sentence or clause, after presenting the situation. The pattern is: [situation], 可想而知. It's a neat rhetorical device - you state the cause and let the listener fill in the obvious conclusion.