单选题 When it____to computer_science, Mary is the best of her class.

单选题 Peter____ start working when it began to rain.

单选题 His new tie____my attention when he came in.

单选题 Physically, boys tend to have an advantage___ girls.

单选题 Wang Ping had to pay his way____school because he came from a poor family.

单选题 As soon as he came to his office, he____himself into work.

单选题 Wemust_(　　)_apositive_attitude_toward lifeif we want to live happily.

单选题 It took my family three years to pay____our debts.

单选题 The grateful girl thanked her teacher from the____of her heart.