The police _____ looking for the missing child.

• A. is
• B. was
• C. are (Answer)
• D. has been

'Police' is a collective noun used with plural verbs in British English.

He is senior to me _____ three years.

• A. with
• B. from
• C. by (Answer)
• D. for

'Senior/junior by' is used to express the difference in age or rank.

She is looking _____ a new job.

• A. at
• B. for (Answer)
• C. after
• D. into

'Look for' means to search for something.

He ran _____ the road to catch the bus.

• A. across (Answer)
• B. over
• C. through
• D. among

'Across' means from one side to the other. 'Through' means in one end and out the other.

She _____ a lot of money on clothes.

• A. spends (Answer)
• B. wastes
• C. uses
• D. takes

'Spend money on' is the correct collocation.

I am confident _____ my chances of success.

• A. with
• B. about
• C. of (Answer)
• D. in

'Confident of/about' — both can be used, but 'confident of' one's chances is more formal.

She was absent _____ the meeting yesterday.

• A. in
• B. on
• C. from (Answer)
• D. at

'Absent from' is the correct collocation.

The film was so boring that many people left _____ the interval.

• A. after
• B. before (Answer)
• C. during
• D. by

Context: people left the film early, so they left before the interval.

He is different _____ his brother in many ways.

• A. than
• B. from (Answer)
• C. to
• D. with

'Different from' is standard British English. 'Different than' is used in American English.

She always _____ her promises.

• A. keeps (Answer)
• B. holds
• C. takes
• D. gives

'Keep a promise' is the correct collocation — she always fulfils what she promises.