只有.才能（以下的例句都以 只有努力工作才能收获丰富 为例） Only by...can...(倒装句）：Only by working hard can we harvest a lot.Only if ...can...(倒装句):Only if we work hard can we harvest a lot.倒装句重点在 前.only if/only by:We can harvest only if we work hard/only by working hard.but:We cannot harvest a lot but to work hard.还有好多好多种说法.