It is well known that nature has provided Shangri-la(香格里拉) with endless natural treasures, making the land happy home for the local people．

Whose schoolbag is this?—It ___________ be Mary’s. It has her name on it.

Did you read a book about customs last week?– Yes, I found ______ very useful to know the customs of foreign countries.

Did you go ___ ___ with your brother last weekend, Tina? –No ,we just stayed at home and watched TV.

Lucy was so excited _______she received an invitation from her friend to visit Beijing.