please can someone explain the use of ことandことに in these sentences please?

しかし、たくさん歩いても、動物を見つけることが出来ません 。 However, even though they walked a lot, they were not able to come across any animals.

二人は山を降りることにしました。 The two men went down the mountain.

Many thanks!

Can someone explain the use of こと and ことに in these sentences please?

しかし、たくさん歩いても、動物を見つけることが出来ません。
However, even though they walked a lot, they were not able to come across any animals.

二人は山を降りることにしました。
The two men went down the mountain.

Many thanks!

please can someone explain the use of ことandことに in these sentences please?

しかし、たくさん歩いても、動物を見つけることが出来ません 。

二人は山を降りることにしました。

Many thanks!

please can someone explain the use of ことandことに in these sentences please?

しかし、たくさん歩いても、動物を見つけることが出来ません 。 However, even though they walked a lot, they were not able to come across any animals.

二人は山を降りることにしました。 The two men went down the mountain.

Many thanks!