Victims of violent crimes often need counseling.暴力罪行的受害者往往需要接受心理辅导。Larger drawings tend to require two or three exposures to cover them.较大的图画往往需要两三张胶片才能拍下来。There's often a trade-off between the need for safety and the desire to work quickly.在安全和高效之间往往需要做出权衡。