Why "have to" not "shall have to"

Test No. [color=blue]errors/inter-8 “Tenses”, question 7

If I get a job in a bank when I leave school, I have to speaking at least two foreign languages.

(a) get
(b) eave
© have
(d) speaking

Test No. [color=blue]errors/inter-8 “Tenses”, answer 7

If I get a job in a bank when I leave school, I have to speak at least two foreign languages.

Correct entry: speak
The error was: (d) speaking

Hi Igor,

As you know a Conditional I sentence consists of two parts - the condition and the result. The result is expressed with will + base verb. You can substitute will with another modal verb such as may, must, can or have to as in the sentence you are referring to.[YSaerTTEW443543]

TOEIC listening, question-response: Who’s Jean Carrier’s supervisor?[YSaerTTEW443543]