関係代名詞の使い方, part 17: 関係代名詞は省略できる?

Here's a fourth rule about leaving out relative pronouns.

You can leave out these relative pronouns: that, which, who, where, when.
You cannot leave out these relative pronouns: whose, what.

Take a look at this rule in action.

• in action - 活動中｛かつどう ちゅう｝で、行動中｛こうどう ちゅう｝で、作動中｛さどう ちゅう｝で、実施中｛じっし ちゅう｝で

○ There's something that I feel really lucky to find out today.
○ There's something I feel really lucky to find out today.

○ The thing which I'm holding in this picture is my helmet.
○ The thing I'm holding in this picture is my helmet.

○ Discovering my helmet had completely broken is what I feel lucky about.
× Discovering my helmet had completely broken is I feel lucky about.

○ The place where the helmet is broken is the front center.
○ The place the helmet is broken is the front center.

○ Someone whose helmet had broken but hadn't realized it would be in a dangerous situation.
× Someone helmet had broken but hadn't realized it would be in a dangerous situation.

Still, I'm surprised that a helmet which hasn't been in an accident can break like this. If it can break just through regular use and maybe being dropped a few times, I think I can't expect it to protect my head in a crash. I'm going to replace it with a hard shell helmet that won't break. Anyway, I consider it lucky to have found out this way rather than in a crash.

If there are some questions (which) you have about relative clauses, please send me an email!