Bill announced his experiment results at the meeting. All the people present were excited at his findings, （complex sentence）
【正确答案】：When/ After Bill announced his experiment results at the meeting, all the people present were excited at his findings.
【题目解析】：本句的要求是将两个单句变成一个复合句（complex sentence）。我们可以将其变成一个状语从句When/ After Bill announced his experiment results at the meeting,（当Bill在会上宣布他的实验结果的时候）。