A film with a broad molecular weight distribution, excellent impact strength and a high dart drop value or moderate dart drop value accompanied by good optical property consisting of a bimodal terpolymer comprising a low molecular weight homopolymer of ethylene and a high molecular weight terpolymer of ethylene, 1-butene and a C6 to C12 a-olefin, or a bimodal terpolymer comprising a low molecular weight polymer which is a binary copolymer of ethylene and a C4 to C12 a-olefin and a high molecular weight polymer which is either a binary copolymer of ethylene and 1-butene, if the low molecular weight polymer is a binary copolymer of ethylene and a C6 to C12 a-olefin, or a terpolymer of ethylene, 1-butene and a C6 to C12 a-olefin. |