根据句意及首字母填写单词。
（1）Do you know the c____  answer to the math problem?
（2）He was so t____  that he drank plenty of water in one breath.
（3）The man is good at playing Chinese c____ 
（4）Many foreign t____  come to China every year.
（5）The Red Army s____ in arriving in Gansu Province in 1936.