Heconcludedhisspeechwitharemarkthatfailure____themotherofsuccess.
B
【句意】本期设计联络会将持续十天才会结束。
【难点】by the time意指no later than the moment that something happens，常与过去完成时和将来完成时连用。
Iam____gratefulforthemanykindnessesyouhaveshownmyson.
Whentheideaofwinninginsportsiscarriedtoexcess,____competitioncanturnintodisorderandviolence.