1．My father bought me an umbrella yesterday．（改为否定句）

2．That is Daniel's key ring．（改为同义句）

3．She is too weak to take part in the activity．（改为同义句）

4．I think she is as slimmer as my sister．（改错，保持句意不变）

5．Mr Wu said，“I'm satisfied with the result．”（改为间接引语）

1、1．My father didn't buy me an umbrella yesterday．

My father didn't buy an umbrella for me yesterday．

2．That/ The key ring belongs to Daniel．

That／The key ring is Daniel's．

Daniel owns／has that／the key ring．

The owner of that／the key ring is Daniel．

Daniel is the owner of that／the key ring．

3．She is so weak that she can't take part／join in the activity．

She is not strong enough to take part／join in the activity．

She is very weak，so she can't take part／join in the activity．

She can't take part／join in the activity because she is very weak．

She is very weak．As a result，she can't take part／join in the activity．

4．I think she is as slim as my sister．

5．Mr. Wu said（that）he was satisfied with the result．