你答对了。
we had the flowers trimmed this morning。今天早上我们让人修剪了这花儿。（别人修剪的）
we had trimmed the flowers this morning。今天早上我们修剪了这花儿。 （我们自己修剪的）
we had the trimmed flowers this morning。今天早上我们有了这修剪好的花儿。（也许自己，也许别人修剪）
查字典have：
固定词组： have something done =let somebody do somenthing for you.(让某人为你做某事）
例 句： I had my hair cut yesterday.
