the government has promised to do【 】 lies in its power to ease the hardships of the homelessA what B that C all what Dwhich 为什么是A.

the government has promised to do【 】 lies in its power to ease the hardships of the homelessA what B that C all what Dwhich 为什么是A.
the government has promised to do【 】 lies in its power to ease the hardships of the homeless
A what B that C all what Dwhich 为什么是A.

the government has promised to do【 】 lies in its power to ease the hardships of the homelessA what B that C all what Dwhich 为什么是A.
do后面是宾语从句,缺少lie in 的主语,当然用what