定语从句介绍科技产品 — 英语填空题
题目
用 who / which / that 填空，完成介绍科技产品的定语从句：
1. The smartphone ___ was made in China works very well.
2. The engineer ___ invented this robot is only thirty years old.
3. The computer ___ my father bought last month is very fast.
4. The scientist ___ discovered the new material won a prize.