"building block"か”brick"
が、積み木の表現になります。
例えば「子どもが積み木遊びをしている」という表現は、
"A kid is playing with building bricks."
となります。
「積み木が崩れそう」という表現は、
"Building blocks are going to fall down."
と言います。"fall down"の他に、"break down"も使えそうです。
Children have lots of building blocks to play with.
Building blocks are usually made of wood, but some are plastic.
Building blocks are usually a child's first set of toys.
積み木 building blocks, bricks
子供たちは遊ぶためのたくさんの積み木を持っています。
Children have lots of building blocks to play with.
積み木は通常木製で作られていますが、一部はプラスチック製です。
Building blocks are usually made of wood, but some are plastic.
積み木は通常、子供のおもちゃの最初のセットです。
Building blocks are usually a child's first set of toys.
アメリカ合衆国 
日本 
