Please help me with these matter may Allaah grant you.
1) I am 21-years old still dependent on my parents. I Al-Hamdulillaah, practice Islam well and follow the Quran and Sunnah. My question is last time I used to fast on Monday and Thursday, however sometimes I get sick but not because of fasting. But after that my dad ordered me not to fast any more. I really want to fast as Prophet said 'it's healthy' but still my dad said that as I am dependent on him and under him I got to follow what ever he asks me. I know that Islam asks us obey our parents but not beyond the limit. So, is it ok for me to fast without my dad's knowledge? Please tell me what's the right thing to do?
2) Is it ok for a Muslim girl to wear a knee length-wider, blouse and pant when out side home?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.

Indeed Islam has given great importance to the parents and made obeying them and being kind to them as one of the best acts of worship by which one gets near to Allaah. Ibn Mas'ood asked the Prophet said: "What are the most beloved actions to Allaah?" He replied: "To pray on time." Then, he asked: "Then what else? He replied: "Being kind and dutiful to the parents." He again asked: "What else? He replied: "To make Jihaad in the path of Allaah." [Al-Bukhari and Muslim]

The Prophet informed us that being kind and dutiful to the parents is the best action after the prayer which is the greatest pillar of Islam. It the narration, the Prophet mentioned being kind and dutiful to the parents before mentioning Jihaad because it is an individual obligation whereas Jihaad can sometimes be an individual obligation and sometimes a communal obligation [i.e. if done by one or few members of the community, then the obligation drops from the rest of them for having to do it]. So if being kind and dutiful to the parents comes before Jihaad when it is a communal obligation then it is more appropriate that it comes before things lesser than obligations, like supererogatory acts of worship.

Therefore, if one has to choose between optional fasting and being kind and dutiful to the parents, then being kind and dutiful to the parents comes first because it is an individual obligation, especially when the parents tend to be merciful to their son or daughter who is harmed by fasting.

However, some scholars are of the view that the parents should not be obeyed if they ask their son or daughter to abandon the supererogatory prayers like the Sunnah of Fajr and Witr and the like, in case they order him/her to completely abandon them.

The most correct opinion is that one should differentiate between the reason they ordered their son/daughter not to fast whether it was due to them being merciful to him/her because of the hardship of fasting, and between what does not cause any hardship like praying the supererogatory prayers. So they should be obeyed in relation to fasting but not in relation to praying supererogatory prayers. Thus, it might be that if one does not have an optional fasting because of being dutiful and merciful to his parents, he would get a double reward: the reward of fasting and the reward of being kind and dutiful to them. One gets the reward of fasting because of being determined to fast, and the reward of being kind and dutiful to the parents by fulfilling their order.   

It should be noted that if the child is able to combine the two things: observing the fasting that one usually fasts, and obeying the parents then this is more appropriate, and one can do so by:

1)     Endeavouring to convince them that fasting does not usually harm the body; in many cases, it is a means of being in good health. This is something that is scientifically proven even by non-Muslims.

2)     Not informing them that one is fasting, by not going to them at the time of siesta [i.e. between Thuhr and Maghrib], if by not going to them during this time does not cause neglecting any need of the parents for her.

As regards wearing trousers under the blouse, a Muslim woman has to wear the clothes that cover what should be covered. In our view if a loose blouse is not worn to cover all the trousers then the purpose of covering all the woman's body is not achieved since it does not cover the lower part of the body, i.e. the limbs. For more benefit, please refer to Fatwa: 83702.

Allaah knows best.