Dare you walk through the ________（沙漠）by yourself?

I'm very happy to see that my seed ________（发芽了）.

There is an old bridge ________（在……上）the river . It has a history of 500 years.

The ground is ________（覆盖）with fallen leaves now.

数10亿人_______________

以不同的方式_______________

想起，想到______ _______

在加拿大________ ________

在春季________ ________