Parsing this text from Mencius
欲辟土地，朝秦楚，莅中國而撫四夷也

The grammatical subject is hidden (Liang Hui Wang, 梁惠王). What we see are four parallel verb-object constructions that describe Mencius' guess of Liang Hui Wang's desires (王之所大欲).

辟土地: 'to enlarge your territories'

朝秦楚: while normally 朝 as a verb means ‘to meet in court', this is no doubt used in the causative sense (使動用法, see fourth entry here): 'to make (Qin and Chu) meet in (your) court'.

莅中國: 莅 simply means 'to come'. 中國 does not mean China, it refers to the Central Kingdoms (somewhat similar to 中原).

撫四夷: 'to pacify the barbarous tribes on the four boarders'.



You may consult D. C. Lau (1984:21)'s translation too: 'You wish to extend your territory, to enjoy the homage of Ch'in and Ch'u, to rule over the Central Kingdoms and to bring peace to the barbarian tribes on the four boarders.'


以若所為求若所欲

The 所-construction nominalises the verb that follows it. So 所為 means 'deeds' (from 'to do') and 所欲 means 'wants' (from 'to want'). 若 means 'you'. But we see two nouns adjacent to each other in 若所為 and 若所欲. For better understanding, you may add 之 in between, indicating possession: 以若之所為，求若之所欲.

以A求B means to seek B with A.

D. C. Lau: 'Seeking the fulfilment of such an ambition by such means as you employ'


Reference
Lau DC. Mencius. Hong Kong: CUHK Press; 1984.