Short sleeves are fine, no shoulders showing. Below the knee pants or skirt is acceptable. Most places will have items for you to borrow if they are very strict. For example, in Thailand I went to the summer palace outside of Bangkok and was given a long sarong to borrow as my long pants still were not acceptable. If you want to be pro-active, you can always bring a lightweight guazey long sleeved top and a light long sarong, keep it in your bag and you will be covered!