When I met him the other day，it was the first time we________each other since we were at school.[ ]

_________, when Marx was already ________, he began to learn Russian.

Do you like her friends—- Yes. One of her friends often _______ her _____her English in the class.

When a new disease breaks out, experts must ________ what to do in the fastest way.[ ]

THe little boys were _________tricks on the girl when their teacher came into the classroom.[ ]