幼时

幼 = 力 + 幺 : Mnemonic symbol: a kindergarten.

Maud Younger (y) is taking care of a kindergarten (幼) in the outhouse's bathroom (ou4). To keep the young (幼) children busy she plays blackjack with them, each time dealing a card by pressing a power button (力). To make life not too hard for them, she is exclusively dealing aces (幺).

时 = 寸 + 日 : Mnemonic symbol: a giant pocket watch.

The sun (日) asks Sherlock Holmes (sh) out for a coffee in the space station's kitchen (Ø2). Looking at his pocket watch (时), Sherlock sees he has time, winks and "thumbs up" (寸).