This study explores the role played by input saliency in L2 acquisition of the time phrase and the locative phrase in Mandarin Chinese. In Chinese the time phrase that indicates when an event takes place and the locative phrase that indicates where an event takes place are similar in that neither can occur after the verb. L1 English L2 learners of Chinese have to learn to place both phrases pre-verbally. The goal of this study is to find out whether learners acquire the placement of the two types of phrases equally well. On the basis of input saliency measured in terms of form-function mapping and type frequency, it predicted that the time phrase will be easier to acquire than the locative phrase. It then conducted an experiment and put the hypothesis to test on learners at an early stage. The findings largely support our hypothesis: Simple time phrases are easier to acquire than simple locative phrases for beginning learners. In addition, the same group of learners had difficulty with both complex time phrases and complex locative phrases, suggesting that structural complexity also plays a role.