〜が
The “who / what” particle
Last unit, は set the topic. Its partner が does three jobs: it points out new info (the answer to “who?/what?”), it marks the target of すき・わかる・じょうず, and it names the part in “AはBが…”. Let's take them one at a time.

だれが きましたか。

フジさんが きました。
しんじょうほうの が
Use が when you point something out — especially the answer to a question word like だれ (who) or なに (what). 🔊 Tap any example to hear it.
が points to NEW information — especially the answer to “who?” or “what?”. The question words だれ/なに take が, and so does the answer you give back.
たいしょうの が
Here's the one to remember: with すき・きらい・じょうず・へた・わかる・できる, the thing they point at takes が, not を. 🔊 Tap an example to hear it.
With すき/きらい (like/dislike), じょうず/へた (good/bad at), and わかる/できる (understand/can), the thing those words point at takes が — not を.
In real conversation it sounds like this — listen for the が:

なにが すきですか。
What do you like?

わたしは おちゃが すきです。
I like tea. (the target of すき → が)

にほんごが わかりますか。
Do you understand Japanese? (が = the thing understood)

はい、わかります。
Yes, I do.
A は B が 〜
To describe a part of something, set the topic with は, then mark the part with が and add an adjective: ぞうは はなが ながいです. 🔊 Tap to hear it.
To describe a PART or feature of something: name the topic with Aは, then the part with Bが + an adjective. “As for A, its B is …”.
れんしゅう
Read the English, say the Japanese out loud yourself, then flip the card to check. Watch your が!