She has had a letter from her mother .(改为同义句）Travelling by train will be cheaper.Travelling by train will be more interesting.(合并成一句） She has visited the Summer plalace.(改为一般疑问）

1.she has receied a letter from her mother
2. Travelling by train will be cheaper and more interesting
3.Has she visited the summer palace
above for your reference

She has received a letter from her mother/She has heard from her mather
Travelling by train will be cheaper and more interesting
Has she visited the summer palace

she got a letter from her mother

She received a letter from her mother
Travelling by train will be cheaper，yet more interesting
Has she visited the Summer plalace？

1.She has received a letter from her mother.
2.Travelling by train will be more interesting and cheaper.
3. Has she visited the Summer plalace?
希望帮到你,祝学习进步

She has received a letter from her mother
Travelling by train will be cheaper and more interesting
Has she visited the Summer palace?

最直接，最简单就这样：Travelling by train will be cheaper and more interesting.
2.时态助动词has提前 Has she visited the Summer plalace？