少不了 (can't do without)

A birthday essential

• Your family is planning grandma's 80th birthday party.
• birthday生日shēng rìparty聚会jù huìcan't do without少不了shǎo bu liǎocake蛋糕dàn gāo。 — "A birthday party isn't complete without a cake."

can't do without少不了shǎo bu liǎo + noun = can't do without

• A can't do without少不了shǎo bu liǎo B = A can't do without B; B is essential: the New Year过年guò niáncan't do without少不了shǎo bu liǎodumplings饺子jiǎo zi.
• The thing that is essential follows can't do without少不了shǎo bu liǎo.

the New Year过年guò niáncan't do without少不了shǎo bu liǎodumplings饺子jiǎo zi。

Certain to happen

• can't do without少不了shǎo bu liǎo can also mean "bound to, certain": so much这么zhè meto make做zuò，can't do without少不了shǎo bu liǎowant / will / need要yàoto suffer挨āito criticize批评pī píng。 — "Do it like that and you're bound to be criticised."
• he他tāis是shìthe lead主角zhǔ jué，can't do without少不了shǎo bu liǎohe他tā。 — "He's the lead; we can't manage without him."

he他tāis是shìthe lead主角zhǔ jué，can't do without少不了shǎo bu liǎohim他tā。

Read it liǎo

can't do without少不了shǎo bu liǎo versus can't be without离不开lí bu kāi

• can't be without离不开lí bu kāi = can't be separated from, depend on: the child孩子hái zican't be without离不开lí bu kāimum妈妈mā ma.
• can't do without少不了shǎo bu liǎo = can't be missing: this这zhè顿饭dùn fàncan't do without少不了shǎo bu liǎowine (esp. rice wine)酒jiǔ.

the child孩子hái zican't be without离不开lí bu kāimum妈妈mā ma。

Recap

Read the full reference: HSK 5 grammar — Sentence patterns.