Tom was happy to get a chance to play _______ football for the school team．（　　）

A．aB．anC．theD．不填

My uncle's reviews on the four great classical Chinese novels may be published _____ the summer of 2021．（　　）

A．inB．onC．atD．for

David is crazy about Chinese history． He ______ visits the museums first wherever he travels in China．（　　）

A．neverB．seldomC．sometimesD．always

Wow， eighteen pink roses! For whom？

________ are for my mum， and the other nine are for my grandma．（　　）

A．FewB．HalfC．ManyD．Most

Max got lost and was trapped in the forest for 10 hours _______ a farmer nearby found him．（　　）

A．ifB．sinceC．untilD．after