1.He is usually careful.But,this time he made a big mistake.
答案But→However
2.Although the sun was shining,but it wasn’t very warm.
答案去掉but
3.Some waste food however others don’t have enough to eat.
答案however→while
4.However it rained hard,they went on hiking.
答案However→Although/Though
5.Child although he is,he knows a lot about electricity.
答案although→as/though
