He started his career as an ........ teacher

Analyze the question: This is a spelling (lexis) question. You need to choose the correctly spelled word that fits the blank. The word is auxiliary, meaning "providing additional support" or "supplementary". An "auxiliary teacher" is a supporting or assistant teacher.

Explain the concept: The word comes from the Latin auxilium, meaning "help". Once you know that root, the spelling becomes easier to remember.

Breaking it into syllables: aux – il – i – ar – y

The correct spelling has:

• aux at the start
• a single l (not double)
• i after the l
• ia before the final ry

Step-by-step check of the options:

• A. auxillary has a double "l" and is missing the "i" after it. ❌
• B. auxilliary has a double "l" (the "i" is there, but the extra "l" is wrong). ❌
• C. auxilary is missing the "i" after the "l". ❌
• D. auxiliary has a single "l", then "i", then "ary". ✅

Answer: The correct sentence is "He started his career as an auxiliary teacher.

Tip: Remember the pattern aux + ili + ary, or think "aux-ili-ary: one L, then I." Other commonly misspelled words in the same family are auxiliary verbs (like "is", "have", "will"), so you will see this word in grammar lessons too.