答案给的是一种策略的两种称呼，能否用roll yield策略？

NO.PZ201601050100001503 问题如下 Intify two strategies lga shouluse to earn a positive roll yiel scrithe specific steps neeto execute eastrategy. Given ththe base curren(the US llar) is trang a forwarpremium, the hee requires the sale of US llforwar resulting in a positive roll yiel The concept of roll yielis very similto forwarrate bianthe carry tra. Here, lga is suggesting a strategy to pursue when there is a negative roll yiel because a heer trang against the forwarbiwoulbuying US llars a forwarpremium insteof selling them. The carry tra strategy of borrowing in low-yielcurrencies aninvesting in high-yielcurrencies is equivalent to trang the forwarrate bias, not against it. 中文解析基于整个题干的背景可知本币是EUR，外币是US因此担心外币贬值，需要short forwaron EUR/US也就是解析里面说的base currency应该是US现在美元存在远期溢价，即F S，所以short forwaron EUR/US头寸，计算roll yielF-S/S也会有正的收益。另外因为美元的利率低于欧元的利率，可以执行carry tra策略，借低利率货币投资于高利率货币，其中低利率货币又叫做forwarpremium currency，高利率货币又叫做forwarscount currency。 “现在美元存在远期溢价，即F S，所以short forwaron EUR/US头寸。”这句话是什么意思呢？为什么美元存在forwarpremium，就要short EUR/US

NO.PZ201601050100001503问题如下 Intify two strategies lga shouluse to earn a positive roll yiel scrithe specific steps neeto execute eastrategy. Given ththe base curren(the US llar) is trang a forwarpremium, the hee requires the sale of US llforwar resulting in a positive roll yiel The concept of roll yielis very similto forwarrate bianthe carry tra. Here, lga is suggesting a strategy to pursue when there is a negative roll yiel because a heer trang against the forwarbiwoulbuying US llars a forwarpremium insteof selling them. The carry tra strategy of borrowing in low-yielcurrencies aninvesting in high-yielcurrencies is equivalent to trang the forwarrate bias, not against it. 中文解析基于整个题干的背景可知本币是EUR，外币是US因此担心外币贬值，需要short forwaron EUR/US也就是解析里面说的base currency应该是US现在美元存在远期溢价，即F S，所以short forwaron EUR/US头寸，计算roll yielF-S/S也会有正的收益。另外因为美元的利率低于欧元的利率，可以执行carry tra策略，借低利率货币投资于高利率货币，其中低利率货币又叫做forwarpremium currency，高利率货币又叫做forwarscount currency。 如题，看了历史提问，还是很糊涂，麻烦老师解惑，谢谢

NO.PZ201601050100001503 问题如下 Intify two strategies lga shouluse to earn a positive roll yiel scrithe specific steps neeto execute eastrategy. Given ththe base curren(the US llar) is trang a forwarpremium, the hee requires the sale of US llforwar resulting in a positive roll yiel The concept of roll yielis very similto forwarrate bianthe carry tra. Here, lga is suggesting a strategy to pursue when there is a negative roll yiel because a heer trang against the forwarbiwoulbuying US llars a forwarpremium insteof selling them. The carry tra strategy of borrowing in low-yielcurrencies aninvesting in high-yielcurrencies is equivalent to trang the forwarrate bias, not against it. 中文解析基于整个题干的背景可知本币是EUR，外币是US因此担心外币贬值，需要short forwaron EUR/US也就是解析里面说的base currency应该是US现在美元存在远期溢价，即F S，所以short forwaron EUR/US头寸，计算roll yielF-S/S也会有正的收益。另外因为美元的利率低于欧元的利率，可以执行carry tra策略，借低利率货币投资于高利率货币，其中低利率货币又叫做forwarpremium currency，高利率货币又叫做forwarscount currency。 1、carry trafinancing from US with lower interest rates，investing to Spanish asset with higher interest rate.2、forwarrate bitrangsell US llwith forwarpremiumbuy Spanish asset with forwarscount

NO.PZ201601050100001503问题如下 Intify two strategies lga shouluse to earn a positive roll yiel scrithe specific steps neeto execute eastrategy. Given ththe base curren(the US llar) is trang a forwarpremium, the hee requires the sale of US llforwar resulting in a positive roll yiel The concept of roll yielis very similto forwarrate bianthe carry tra. Here, lga is suggesting a strategy to pursue when there is a negative roll yiel because a heer trang against the forwarbiwoulbuying US llars a forwarpremium insteof selling them. The carry tra strategy of borrowing in low-yielcurrencies aninvesting in high-yielcurrencies is equivalent to trang the forwarrate bias, not against it. 中文解析基于整个题干的背景可知本币是EUR，外币是US因此担心外币贬值，需要short forwaron EUR/US也就是解析里面说的base currency应该是US现在美元存在远期溢价，即F S，所以short forwaron EUR/US头寸，计算roll yielF-S/S也会有正的收益。另外因为美元的利率低于欧元的利率，可以执行carry tra策略，借低利率货币投资于高利率货币，其中低利率货币又叫做forwarpremium currency，高利率货币又叫做forwarscount currency。 看了之前同学提的问题，是carry tra 的另外一个说法是tra on forwarrate bias，那其实就是一个策略啊，题目要我们给出两个策略，但实际上，我们的回答其实只是一个策略，用来两种说法来描述而已？