Simple Past Tense VS Past Perfect Tense

When I arrived at the office, the meeting .....

• start

• had started

• started

• has started

A month ago, we ... a big problem at school.

• make

• had made

• made

• has made

I .... to market yesterday to buy some food and drinks.

• went

• go

• had gone

• has gone

When we were on the hill, we ..... the gorgeous scenery.

• see

• saw

• had seen

• has seen

We ---- the mountain last Sunday.

• had climbed

• climbed

• has climbed

• climb

I --- an unforgettable moment when I was child.

• has

• have

• had

• had had

After my mother ---- our breakfast, she cleaned the kitchen.

• had served

• served

• serve

• has served

I ---- the medicine in the drugstore last afternoon.

• buy

• had bought

• bought

• has bought

They ---- hard before they took examination.

• studied

• had studied

• has studied

• study

My childhood ---- so happy.

• was

• were

• are

• is