Future time expressed with simple present tense

How can you explain to the students the use of simple present meaning future in an effective/easy way?

Can only verbs such as begin, start, end, leave, and arrive + time expression refer to future activities?

The verbs you mention—begin, start, end, leave, and arrive (and others having to do with scheduling, such as open, close, finish, come, and go)—are frequently used with the simple present tense along with time expressions to refer to future activities. In addition, other verbs can be used to announce scheduled events or to talk about them, usually with a time expression:

(a)

The South Sail Club gives its annual dinner next week.

(b)

I fly into Bombay at noon, and then speak at the conference at 3:00 p.m.

(c)

Bettina graduates on the 25th. I have no idea what she’s going to do after that.

In addition, a verb in a subordinate clause referring to the future time also appears in the simple present tense in certain situations. The future time is determined by the main verb or by the context; the verb in the subordinate clause appears after the subordinating conjunctions after, before, until, when, as soon as, and often, if. The verb in the subordinate clause may be any verb – not just those referring to scheduled events, timetables, or travel.

(d)

I’ll call you after the party is (NOT will be) over.

(e)

The young couple is preparing a room for their baby before he arrives (NOT will arrive).

(f)

You’d better not leave your job until you have (NOT will have) another one.

(g)
When John finishes (NOT will finish) undergraduate school, he’s going to attend Harvard Medical School.

(h)
Please let us know as soon as you get (NOT will get) into town – we’ll have lunch.

(i) If it rains (NOT will rain) tomorrow, we won’t be able to go on the picnic as planned.