用…来 / 通过…来【yòng … lái / tōngguò … lái】

来 between two verb phrases links a method to a purpose: do the first thing in order to get the second. The method comes first, usually with 用 ("use") or 通过 ("through, by"), and the purpose follows 来.

用 takes a tool or a thing; 通过 takes an activity or a channel, and is a little more formal.

Without 用 or 通过

The first phrase can be any action, with no 用 in front. 来 still says "in order to".

Where it goes wrong

English often puts the method last: "solve it with this method". Chinese keeps the method in front.

• × 我们来解决问题用这个办法 → 我们用这个办法来解决问题

This 来 doesn't mean "come". In 我来做, "let me do it", 来 has a different job, with its own point.