Conjunctions: als, wenn, wann or ob
In these exercises, you must decide whether to use als, wenn, wann or ob. It can be confusing, since in English we use the words "when" and "if" to express all of these ideas.
Use als when you are talking about a general time in the past: for example, "Als ich kind war...(When I was a child...)." Als can also be used to mean "as" or "than."
Wann is a question word, used to ask when something happened or will happen. It can be used in statements when referring to the specific time that something happens, such as in "I'm not sure when he will get here." Wenn can be used to mean "if" or "when." It is a subordinating conjunction used to connect conditionals (If it rains, the sidewalk gets wet), express the notion of "whenever" (He'll call when he has time), as well as indicate the subjunctive mood (If I became a millionaire, I'd buy a Ferrari). If the word "if" can be replaced by "whether" use ob.