The phrase "a thing which can" is correct and usable in written English.
It can be used to describe an object or concept that has the ability to perform a specific action or function.
Example: "A smartphone is a thing which can connect to the internet and run various applications."
Alternatives: "an item that can" or "an object capable of".
Casual games are little time-wasting games (at least in my dystopian world) which appeal to the masses, so mash those up with a social aspect and you should, at least in theory, be on to a good thing which can spread games more virally than the Mini-Clips of this world, which don't have an underlying social network, thus creating more traffic and more data about the user.
The hypothesis of a possible existent thing, which can both exist and not exist, leads necessarily to positing a cause that makes it necessary (by virtue of another).
For example, take the interpretation of Mill on which he believes that there is only one intrinsic value — happiness — but that happiness is a complicated sort of thing, which can happen in each of two different ways — either through higher pleasures, or through lower pleasures.
Evidence, whatever else it is, is the kind of thing which can make a difference to what one is justified in believing or (what is often, but not always, taken to be the same thing) what it is reasonable for one to believe.
Then there's the whole good-deeds-and-works thing, which can absolutely ruin a weekend.
And since Joe is not an event, he is not the kind of thing which can be caused.
However, while such statistical tests demonstrate that rongorongo is consistent with a syllabic Rapanui script, syllables are not the only thing which can produce this result.
Still, there's football, lovely football, the only thing which can bond adult men in friendship.
So absurdly shallow, flighty, and anger-focused is the current political milieu that, if a few things which can go wrong do wrong -- like an economic downturn, a terrorist attack, a geopolitical humiliation -- Trump may not only win the election but sweep to victory.
Jesus is telling Nicodemus that the kingdom of God is not in the miracles which I am working; it in a state of things which can only be appreciated by a radical spiritual change.
If a number of things which can go wrong for the highly capable Clinton do go wrong.
