I called at the Smith's yesterday.

　　我昨天去了史密斯家。

　　I called on the doctor yesterday.

　　我昨天去拜訪了醫(yī)生。

　　I called at the doctor's yesterday.

　　我昨天去了醫(yī)務(wù)室。

　　另外，call on還可以"號召"，后面往往接動詞不定式作賓語補主語。如：

　　The headmaster called on the students to work harder.校長號召學生們更努力地學習。

　　call for

　　1. 要求：

　　He sat down and called for some beer.

　　他坐下來要了一些啤酒。

　　The crew of the ship are calling for a raise in pay.

　　這艘輪船上的全體船員正在要求增加工資。

　　2. 需要；必需：

　　To be a nurse calls for endurance and patience.

　　作一名護士需要有毅力和耐心。

　　This good news calls for a celebration.

　　這個好消息值得慶祝一番。

　　3. 去取；來��；去接；來接：

　　I'll call for you at seven.

　　七點我來接你。

　　Shall we send these books, or will you call for them?

　　這些書是我們給您送去，還是您來取呢?

　　4. 預期；預示：

　　The weather forecast calls for snow flurries tonight.

　　天氣預報預示今夜有小雪。

　　5. 規(guī)定：

　　The traffic regulations call for that all vehicles should keep to the right.

　　交通規(guī)則規(guī)定車輛一律靠右行駛。

　　6. 大聲叫喊要…：

　　The bricklayer on the roof was calling for more tiles.

　　房頂上的瓦工招呼再送些瓦上去。call in叫(某人)進來; 來訪

　　Call in this evening if possible.

　　可能的話今晚來一趟。

　　找〔請〕來

　　How many friends will you call in?

　　你將邀請多少位朋友?