My friend, philosopher and guide _________ my father.

• is
• are
• were
• has
Correct Option: A  [ is ]

Remark: "friend, philosopher and guide" refers to one person.

___________ many times every winter in

• It snows
• It snowed
• It is snowing
• It is snow
Correct Option: A  [ It snows ]

Remark:

Unless we ______ now we can't be on time.

• will start
• start
• starts
• will be starting
Correct Option: B  [ start ]

Remark:

The furniture in this room _______ made of teak.

• are
• have
• is
• No correction
Correct Option: C  [ is ]

Remark: Furniture is an uncountable noun and is not used in the plural, so furniture is a singular subject.

The student, as well as his teacher ________ going on the excursion.

• have
• has
• were
• was
Correct Option: D  [ was ]

Remark:

Not only my parents but also I _______ regretting the change of school.

• are
• is
• am
• No option is appropriate
Correct Option: C  [ am ]

Remark: in case "Not only...but also" the verb should agree with the subject closest to the verb.

Every girl and every boy ________ given a silver medal.

• are
• was
• has
• have
Correct Option: B  [ was ]

Remark: If a subject is modified by the words "each" or "every" that subject is singular and will take a singular verb.

One of the boys ________ been given a book.

• have
• are
• has
• were
Correct Option: C  [ has ]

Remark: "One of" is followed by "plural noun/pronoun" and "singular helping verb"

Each of the students _______ given a task to complete.

• were
• was
• have
• have been
Correct Option: B  [ was ]

Remark: If a subject is modified by the words "each" or "every" that subject is singular and will take a singular verb.

The horse and the coach ________ arrived.

• have
• have been
• would
• has
Correct Option: A  [ have ]

Remark: When two singular nouns joined by "and" refer to the same person or thing, the verb is singular.
But here article "the" used twice before each noun to indicate two different subjects, thus "have" used.